In any kind of empirical subject, especially in demography,
is very important to know something about the sources of data on which one's making one's pronouncements in demography.
Many of these are secure. Some of them are insecure.
And like in any other aspect of numerical study, is very important to know.
How firm are the foundations of the data on which you're basing your models, your projections, your your your high level theories and all the rest.
And this this lecture is really meant to be an introduction to where the demographic data come
from and how they're used and how they've developed over time and what they're collected for.
And one of the basic points, which I got to admit, is that on the whole and generally speaking,
demographers are parasitic on the body politic in the sources of demographic data,
demographic data, all the data that demographers use are not collected primarily for the benefit of demographers.
As you might imagine, they are connected for quite other other reasons and partly for that reason.
Sometimes they are not really very suitable for demographic studies.
One has to tweak them and modify them and just them so that they make sense in demographic terms.
So without further ado, let's let's have a look at what's on offer.
Generally speaking, it's been the business of states to increase their population over time and therefore,
states always taken an interest in what we would call demographic statistics,
not, of course, for demographic gratification of academics, but for their own state concerns, especially in the past.
The more people you had, the more power you had.
And this this remark from Proverbs sums up the sort of assumption about the merits of large population size,
which will be accepted equally by Sennacherib and Starlite. And we will go on to look at that.
That that in while the more detailed. The main purpose of the collection of data,
which we demographers use to for our estimates and our projections and all the rest have been in the earlier time for
purposes of controlling and maximising population and later on for purposes of enhancing the welfare of the population.
And I think it's fair to say the history of the gathering of data, which we call demographic by states, has been an evolution from, as it were,
an earlier a rather harsh authoritarian pattern of collecting data because it's useful for
states and for rulers to know how many people they have they can tax conscripted into the army,
conscripted to forced labour, to build canals and so forth on the one hand,
and that society has evolved and become more liberal and softer and enlightened.
We see the beginnings of concern for the individual welfare started to materialise until now.
For the most part, in most systems of demographic data gathering, it is individual welfare, health,
security of the abolition of poverty, which is the driving force for the collection of data which demographers use.
Not so much. The power bases, which previously was, was the case in earlier times.
State security and religious monitoring was quite important to to minimise subversion in Japan.
As some of you may know, there was a considerable possibility that in the early 17th century,
Japan might become Catholic as a result of missionary activity.
The Japanese, having seen what happened to the Philippines under Spanish control, which had become Catholic,
did not wish this to happen in Japan and that the growing Catholic population was suppressed and its suppression was guaranteed.
Or at least an attempt was made to ensure that people conformed to Shinto practises and not Catholic practises
by obliging births and other unions to be registered in the Shinto shrine and forbade it in Catholic Quansah.
Somewhat similar reasons parish registers in Protestant England were developed
in 1038 in order to ensure the population was having its religious events,
which of course was then universally observed taking place under the aegis of the new Anglican Reformed Church,
not of the old Catholic Church membership, which was regarded as being subversive in those difficult times in the two year period,
which would have read about or seen on the telly where Catholic records and Seaver's
was thought to be very serious security threat with risks of encouragement,
invasion by Spanish monarchs to restore Catholicism and all the rest of it.
A number of other examples of that can be thought of. Mobility is something else.
Which populations which states in the past were very keen to control.
We owe to the very severe, heavy control of population by Chinese imperial authorities from the earliest possible dates of view to that,
a very substantial body of Chinese population data going back to eighty four or even earlier,
which enables some reconstruction of the Chinese population to be made over two millennia,
is the longest series of population estimates based on actual data which we've got,
even though it's rather fragmentary and owes itself to this very severe system of registration of of Hustle's to make
sure they stayed where they were to ensure that the authorities knew where they were for purposes of of of taxation,
for purposes of of assembling workforces, for building those great canals which characterised the Chinese infrastructure and all the rest of it.
That continues to the present day. The hukou system of household registration in a modern guise is still a much criticised
element of of control of the population movement in communist China to this day.
So not all of these state control elements have gone away by any means.
And there is also still in Belarus, the old Soviet system of a piece of an internal passport,
also designed to regulate internal movement and prevent people living where they want to.
In due course, personal leave starts to emerge, became useful for individuals.
It's always been useful for people to have some record of who they are.
And in the absence of written documentation carried by individuals in those times in the past,
the fact that the other birth or their baptism was recorded somewhere in an official document was
a great value to them and became increasingly valuable to them for purposes of identification,
for purposes of proving that inheritance and their entitlement and the legitimacy of their children and all the rest.
We move, I suppose, from the 16th, 17th century onwards into a time where were more enlightened governments,
we became much more interested in looking after the welfare of the people and data that were increasingly collected,
not just for the the the state's reasons that I mentioned earlier on, but for allocating resources,
for monitoring health trends and population distribution and overcrowding and all sorts of other aspects to do with welfare,
which were generated to the now very substantial set of population questions which we have in modern day census,
where there are 50 or so questions mostly to do with with helping the state to to to manage population welfare rather better than previously.
So what kind of data are these are two, really three basic sorts of data which are collected which are useful for demographers.
The one less obvious one is the census. The census is a regular universal count of the population and an evaluation
through questions of the condition of the population is meant to be universal.
It is meant to refer to a specific point in time, preferably a particular day in a particular year is a periodic, usually held of a 10 year interval.
In some countries, a five year interval and the numbers of questions have increased over time.
There are about 50 in this this questionnaire here. They are based on households.
The household is a basic unit,
and every person in the household answers answers to questions or has the questions answered for him or her by the so-called head of the household.
Appointments are raise later on. The other major source of population information comes from so-called vital registration.
That means that events relating to an individual's life history are recorded as they happen in the past.
These will be defined in religious terms as a baptism, as a marriage, as a burial.
In more recent times, those have been transferred, as it were, to the secular equivalent of births, marriages and deaths.
These, in the nature of things, happen all the time.
They require some system whereby individuals are compelled to recall these events within a certain space of time with the happening and under penalty.
And that, of course, requires some kind of national organisation to collect that.
Either the ecclesiastical parishes of the past,
collecting data on the on baptisms and burials and marriages celebrated in that church or more recently,
register offices held up and down the country.
In the developed world, in the nature of things, you've got to be quite a developed country before you can afford to have a system which records,
which registers and vital events as they happen because it requires a structure of collecting data around the country.
You can't do it by survey. It's got to be recorded as it happens, more or less on the spot population registers or development of that.
These are systems where usually on a local basis, not only are these events recorded as they happen,
but also a running total of households and their composition is kept on the basis
of an evaluation of a census type continuity up to date by adding the births,
recording of marriages, deleting the debts running total of population and the characteristics of a population
that appears to be the future for population accumulation in the developed world,
as I've mentioned later on. We need these two sorts of data because we're interested in risk.
It's quite interesting to know how many birthright in particular, country in particular.
It's quite interesting how many deaths there are, what we really want to know for in order to compare trends over time,
in order to compare different countries and different populations. What I really want to know is what's the risk of it?
What's the risk to the individual of dying? What's the risk to the individual of having one or two or three children in the course of their lifetime?
For that, you need to put together two kinds of data.
You need to put together the population at risk, typically derived from the census or from some large scale survey.
And to relate to that, the number of events as they happen, you divide the number of events by the population risk and you get some kind of rate,
as I'll explain next week, with a simple way of doing that is simply to work out a so-called crude rate.
The number of events divided by the total population risk of that event times a thousand to make it into a nice round number.
So you've got a crude birth rate or crude death rate in Iran, as in this example, it was 19 births with population in 2009.
In this country, it's about 12 births, 1000 population, and in Uganda, about 50 births per thousand population.
More informative measures use more data and we'll see in the next decade or two how we how
we use rather more refined methods to give intuitively more informative measures of risk.
But enough of that later on. I mentioned that.
Collection of data, which we use for demography, is almost all the states themselves because states for their survival,
ever since they have been states have an interest in working out how many people they have to tax to it, to draught into the army and so on,
and in particular to make sure their numbers aren't declining rather than rather than increasing,
because especially in the past, where it was almost impossible to improve productivity,
the output of a particular country would depend very much even more than it does at the moment on the number of people in that country.
And so the more the better. Hence the growth of empires and and the growth of attempts to enumerate.
And these go right back to ancient Sumer in the Fertile Crescent, to Egypt, to Babylon.
Several examples in the Bible, one of which greatly complicated an attempt to introduce population registers in Britain later on.
I have I have time to mention in Rome, the census every five years for 800 years, almost none of which have survived,
thanks to the tendency for barbarians to burn the place down from the sixth century onwards.
We do have some census records from Roman Egypt, which are extremely instructive since some individual question is from Roman Egypt,
some of which suggests that brother sister marriage was quite common.
Following the example of the Ptolemy's,
you recall that Cleopatra was notionally married to her brother and other people seem to think this is a good thing to do.
The activities of the upper classes and all sorts of things emerge from these these bits of data which survived from the ancient past.
China, as I mentioned, the hukou system of household registration, insofar as that the data were collected when dynasties were were intact,
has given us bits of information over the last two thousand years,
which will enable this immense set of estimates of population to be to be consolidated by adding them all together.
Here is a graph. It's a bit squashed in showing Chinese population history of the last two thousand years, the dots,
different coloured dots are periods of actual actual enumerations or collections of enumerations.
And you can see that there are periods of time when when these are not collected because the
Chinese history is one of the establishment of powerful dynasties which can maintain this system,
followed by periods of of interregnums, of chaos,
during which time records are not collected and those which were collected might have been destroyed.
But you can see that we see periods of growth and we see periods of decline,
particularly after the Mongol invasions of the 14th century, sort of 13th century,
and then very rapid decline in increase under the chin in the 19th century and more
rapid increase of the present day than heading for a fall in about 30 years time.
So really very interesting information can be collected for some countries
over a long period of time from sources not intended to gratify demographers,
but for human sciences students or scholars, but nonetheless do serve to produce all sorts of very valuable information to give back to Japan.
I've mentioned Korea was similar.
Interestingly, at the beginning of the early modern period, we start to see modern type censuses being being introduced,
particularly in those countries which were under threat of demographic decline.
As I'm sure you know, the early European colonies in North America were quite a vulnerable state.
Some of the early ones on the continent, for example, disappeared without a trace within two years.
Others were very precarious demographically because the death rate initially on the colonies was extremely high and their survival was uncertain.
So we have censuses of a local kind going back to the 17th century, and in Europe we have one from seventeen hundred and three in Iceland.
That's thought to be the first modern census in Europe precisely to evaluate the size of the surviving Icelandic population,
which had endured what many historians call a millennium of misery.
Thanks to the deterioration of climate. We've got particularly bad in the 15th and 16th centuries and reduce the Icelandic population to that level.
There's still one sophisticated enough to hold a census of seventy thousand three,
and that's where from that all of us, we start getting more and more censuses in European countries.
Here are some some pioneer demographic sources, the doomsday book you have heard of, not actually a census, it was an inventory of property.
After the Norman conquest, the king obligingly decided that all all property was his and that everyone held property as his tenant and rules.
A book was simply an inventory of property, which happens to mention people in a way which enables us to reconstruct the population.
Given all sorts of assumptions about household size, which I won't go into.
But it is a unique source. And although there are other kinds of enquiries later on, there's nothing quite like Doomsday Book anywhere else.
From the 16th 17th century we saw getting modern censuses, as I mentioned, first of all,
based on individual basis and then based on a much more rational household basis,
starting really in the middle of the of the 18th century with Sweden in 1749 and then up to the present day,
some countries didn't hold census until quite late. As I mentioned, the Russian Empire, Motley's 1911 and a modern census in Japan, not until 1920.
We owe to these old gentlemen, I'm afraid, ladies, women, early democracies.
I'm sorry to say, quite different. Now, the registrar general is female and has the previous one as well, but not at this time.
It is these characters who turned these state statistics of the very first time into into demography.
It didn't previously, they were simply not used for any kind of scientific or broader political purpose.
John Graunt, concerning who Philip Krieger is, the world's greatest expert,
really began demography in his book of 60 65 called Natural and Political Observations Upon the Bills of Mortality.
Those are authority records of deaths kept every week by the company of parish clerks categorised by
cause and also births in order to forewarn particularly the onset of plague and other epidemics.
Their major function was an early warning system for a rise in deaths, which indicated that the plague had returned.
Graunt use these data, which were published, which were collected, published, printed, made public in order to analyse the population of London.
That's the first book of demography using these state statistics collected in this in this case for very practical reasons,
turning it into an analysis of population change with all sorts of novel discoveries previously hadn't been appreciated at all.
He, like almost all the other Englishmen here, was a fellow of the Royal Society. Quite a few of the others were clergymen.
So an early German precursor of Maltose was a clergyman.
Malteds himself, of course, was a clergyman. Richard Price was a clergyman, and most of the English people also were fellows of the Royal Society.
And we see we see in this chronology of turning data collection for state purposes into a kind of science,
a kind of microcosm of the rise of the Enlightenment in in Western Europe,
where all sorts of other kinds of scientific enquiry of a statistical and rational kind were starting to accelerate.
Hala, just just to remind you, a highly lived part of his life in a house in the new college lane,
which you can see with the plaque on the wall if you walk down there.
And of course, like many of these characters, he wasn't just interested in the model.
He was interested in everything, all sorts of aspects of natural science and how he was the first person to be
able to plot the trajectory of a comet and and correctly predict its return,
even though its returns projected to be at a time when he would be dead.
He comes back every 75 years and he will be alive, I hope, in 2050 once you're coming back.
And Hally, the demographers also had the astronomer who's also had all sorts of other things as well.
Great days for the polymathic. The.
The registration of is one of the. Bucket, if you to drown such things in silence and love.
This is just to remind you how registration changes from from religious to vital events.
Originally, we have this these parish registers from 50 to 38 in England,
which is when the statistical curtain goes up on the English population and generates
data which we've been able to use to reconstruct population and birth rates.
The bills of mortality I mentioned these these enquiries into the cause of death in urban areas.
First of all, London and then in provincial towns and then from the 17th century, the start of some attempt to evaluate things on a civil basis.
The protectorate under Oliver Cromwell briefly introduced the civil registry place,
a religious one not because they were religious, but because they felt that they were they were not sufficiently efficient.
In fact, for all sorts of complicated reasons, we didn't get a compulsory registration of births and deaths in England until 1837,
something which attracted considerable comment on the part of a foreign observers.
And then it got more and more complicated as time has gone on, particularly with the proliferation of administrative registers,
whereby lots of things you do probably without already noticing it, are now incorporated into fairly comprehensive sets of data.
Your National Health Service number, your national insurance number, all your driving licence, your tax records, your TV licence, the latter,
which covers 97 percent of households in the country,
all producing registers which you can possibly put together in a population register to replace the census, as we will see in due course.
This is just an example of what you get from the parish registers.
This is not the actual register itself.
It's an abstract from it, and it shows the difficulty of using of using data not collected for demographic reasons to try and turn it into demography.
Because what you've got in the parish register is simply a where the parish was the location of the parish at the date of the event.
The fact of the event where it was a baptism, a burial or a marriage, these are religious categories.
Forget not not not demographic ones.
And the name of the person dying of being buried or being married or being baptised and in the latter case of the name of their parents.
And so you don't have their ages, for example, you don't have how many previous children they got.
You've got to work this out. And you do this by a complicated system known as well.
It's essentially simple, very tedious, called called a record linkage,
whereby you plough through these registers making a note of every event and every name as it arises,
and then making a note when the same name crops up, making assumption, of course,
that the surnames remain reasonably constant, which by this time they were.
Once you can do that, you can slowly start to rebuild lives.
You can rebuild lives from the individual story of the birth baptism of the individual at a particular time,
the subsequent burial as a child, if they die early, their subsequent marriage, the baptisms of their children and their subsequent burial.
So if you if they survive to a later life, if they don't move away from the parish,
you have a complete record if you can link these these events, because then you can work out how much time elapsed from one to the other.
And here, for example, is an example. If you look at Thomas Baptist, you will see that Thomas aboutus was was baptised on June 24th.
Seventeen sixty two, and poor Thomas Battis was buried in the same year on September 21st.
So you've already reconstructed a bit of that person's brief life.
You've got how long he lived. And the same kind of thing enables you to work out the average length of life, the average age where people got married,
proportion of people who got married in the course of their lives, how many children they had on average, the birth intervals of those children.
So you can infer whether or not family planning was being employed, although certainly not all sorts of other details.
As long as you can collect enough data, link it in registers which are sufficiently intact over a long period of time.
And that, of course, is quite a big gift because these are hundreds of years old. They get burnt in fires, they get eaten by mice.
They use this wrapping paper. Lazy clergymen don't keep them safe from water or may soon dispose of them.
Nonetheless,
it is possible that the ten thousand parishes of England to recreate population using a sufficient number of hundred of these parish reconstructions.
So we have very good data about demographic behaviour of the kind which actually lose the 19th
century because the parish registers then become inadequate to cover the whole population.
But this is one of the areas like astronomy where amateurs are really important, really,
if you could not have used the parish registers to reconstruct the population of England and Wales had
not been for an army of local amateurs willing to go through this rather numbing task of an individual,
a record linkage and family reconstitution. These are just to show you what the bills of mortality actually look like.
These are posters stuck up in public places.
You can't read the detail, but on the left, we've got a weekly one for one of the London parishes, indeed for for the plague.
And you can see how the causes of death, I don't read them or not are are all specified.
And what have we got here? Well, got aged 45. Well, that's that's all right.
That's not allowed nowadays. You can't die of old age. Going to die of something specific age.
You almost certainly means malaria. What else have we got?
We've got childbed 42. That that's that's that's, um, maternal mortality.
Childbirth. We've got smallpox here. One hundred and nine I think it is.
We've got suddenly suddenly one and killed by a fall from the belfry as All Hallows, the Great Wall sound of a very excessively specific grief.
Three frighted three. The important thing here is a plague which is here plague seven thousand one hundred sixty five.
That's that's that kind of thing is a reason for the publication of these things.
So you could you could know what was going on, your thoughts. You could take whatever futile steps there were to control the plague,
the one exception or two exceptions being one getting out of it as soon as possible and to stopping other people getting out of it to it's spreading,
as you will see in a moment. This is the general battle for sixty sixty five, the plague showing the casualties for for each of the parishes.
These are the parishes. They are not the cause of death. Here are the cause of death.
The same ones as we saw some of them scientifically sensible because the symptoms are similar to the ones we use nowadays.
Others are less scientifically respectable. Teeth and worms is one, for example, which is not terribly helpful.
Some curious Connexions had mould shot, which I don't know if he's here or not, is responsible for that.
We now know because the head is like a cannibal and what we got here is a plague death sixty eight thousand five hundred ninety six.
That's sixty eight thousand out of a population of about four hundred and fifty thousand.
So enormous casualty rate from the plague and this severe.
It's not the only one where that's where that happened. This is just to show the what I call the mostly futile pattern.
These this is a kind of cartoon strip from all the general bills showing the progress of the plague.
People, people dying in their bedrooms, the dogs being killed.
It was sort of a dog spread plague, completely mad dogs killed rats, which by plane, but dogs being beaten to death in the street of here,
of birds falling out of the sky and also the court making a way out of London in the royal villages with
old St Paul's Church in the background here we have here we have quarantine while the sensible things,
armed men, as you see, stopping people leaving London with the hope of stopping the plague, a theoretically sensible thing to do here.
A mass burial is going on, first of all, coffins and then cart loads of people because there weren't enough coffins.
And then eventually the plague goes away and people start coming back.
And those people in the background, a remarkable episode.
And this is just a provincial one just to show how in later times these bills could be enlivened by by by tasteful poems,
which you can see here at the bottom, but you can't read all sorts of literary effusions.
These parish registers eventually became inadequate for all sorts of reasons, the increase of dissent and scepticism, the revival of Catholicism,
the development of Methodist and Quaker and other forms of Christianity which didn't use the Anglican churches for for their baptisms anyway.
They did for their burials a large extent meant that the parishes registers became less useful as time went on and also the growth of data increased.
The state was becoming more intrusive in a benevolent way,
but by this time there was a realisation that it was a state's responsibility to look after the welfare.
Citizens and therefore, there was a demand for data measuring health, measuring population trade trends and all sorts of other things,
not the least being the 18th century population controversy in the absence of census.
It was almost impossible to tell whether the population was growing or not and people of considerable knowledge and mathematical ability.
We're engaged in a considerable role in the Asian century, as well as where the population was going up or going down.
It was, of course, going up, you know, but this is difficult to be sure and send.
One of the reasons for the census was this to resolve this population controversy more practical was the need for good data for life insurance,
life insurance as part of the general enlightenment of society.
And its development had been growing from the well of the 17th century onwards, even earlier in Italy.
And that, of course, does require for its solvency to have good data on risks of mortality and expectation of life,
which are very difficult to get as one reason why they have been highly praised.
His life table for the population of Breslau in sixteen seventy two, as I mentioned here, by 800 802,
there were one million people insured defending societies and that required demographic data to work out the balances
with the payments they made and the payments that they received and when when when they died or or when their insurance,
their insurance was mature. And that was lacking. There's always a dark side to these things.
I've mentioned the severity of the ancient Chinese registration system.
I have a quote somewhere here showing what what would happen to people who ignored the census.
It says this dates back, back from the earliest date, around eighty two.
There were strong penalties for evasion. And the official statement was that if the numbers were wrong because they were double checked,
then the family were placed on the list of those liable for military service.
Any common people who hide in the census will be punished according to law and draughted into the army.
If, in their search, the military come across minor officials who have suppressed the facts.
Those officials are to be decapitated and other severe penalties were imposed right up to the president in recent times, avoiding the folks.
Scotti the German population register just before during the Second World War was a very,
very serious issue and might lead to being sent to a concentration camp and other penalties were imposed elsewhere.
And this sometimes manifested itself in in very severe retribution to census officials who got things wrong.
Even honestly, the Stalin was very keen.
Like all autocrats on population growth, he felt that the population of the Soviet Union in 1837 ought to be one hundred and seventy million,
in fact, turned one hundred and sixty two million, eight million people short.
That's because the cost of the enormous mortality in the Ukrainian collectivisation
famine plus the beginnings of of the heavy mortality of the great terror.
Over a million people died. As you see, that the Census Bureau came to a bad end is just the more senior officials will give you.
I don't know. And in fact, the whole census of 1937 was effectively hidden from public view.
We didn't know about it until Mr. Gorbachev opened this campaign in eighteen nineteen eighty five or whatever it was.
That was the first time that we had any clue there had been a Soviet census in nineteen thirty seven.
There was no one in 1939 which came to the right answer amazingly enough.
And that's when we knew about we did not know that 1837 at all.
Perestroika as well as before. These just posters that said it's just for adornment.
There's also a complication if instead of having autocracy, you have democracy if you want.
Nigeria is an example I would dwell on in a moment in Pakistan because of controversy about about the battles between different provinces in Pakistan.
There were five senses postponements in the last decade.
The Lebanon census of 1932 was the first and so far the last that unwisely allocated the offices of state.
According to the relative size of different population.
Groups such as the Maronite Christians on the basis of census results were awarded the post of being president.
The Sunni Muslim, on the basis of the numbers, evaluations and census were awarded the post of prime minister and the Shia Muslims
were awarded the post of Speaker of the Parliament since nineteen thirty two,
of course, because a different pace of demographic transition, the balance of numbers in Lebanon has radically changed as well.
Of course, all kinds of terrible turmoil, is it? By no means. It is quite impossible now for a census to to confirm those those positions.
In fact, other things have ever taken them. But there hasn't been a census since because it was so it was so much upset, the apple cart,
as it were, with unforeseeable consequences that a different arrangement has come to.
This is the problem of what happens when you add democracy to federal report of the solution.
And the census in Nigeria and the Constitution requires that the different major
provinces of Nigeria have representation in the parliament according to population size.
Accordingly, it becomes it becomes highly beneficial to these different regions to to maximise the number of people,
particularly when there is ethnic religious conflict. The northern part of Nigeria, as I'm sure you all know, being mostly Muslim,
the southern part being mostly Christian and animist with with increasing tension between them.
And as you can see, the census of nineteen sixty to forty four point five million people,
this were thought to be defective, too high for all sorts of reasons.
It was held the next year. And amazingly enough, another 60 million people materialised as a consequence of all sorts of encouragement.
To maximise numbers for political and economic ends that was revised back to fifty five point six and a census could not be held again until 1991,
and that there is the census of 2006 has generated continuing controversy.
And alas, as you know, I'm sure a religious conflict in Nigeria is getting worse rather than better.
The developments in vital statistics are particularly interesting because they are closely
connected with the rise of modern scientific medicine and the rise of epidemiology.
The the value of demographic statistics is strongly highlighted by the work of William Farr,
John Snow and others in identifying the causes of major mortality in Britain at that time.
And it could not have been done if it not been for the collection of statistics and the manipulation of statistics with with with modern methods.
Let me give you an example. This is the famous example of Dr John Snow and the Broad Street pump.
Cholera, which is a disease native to Bengal, first arrived in England in I think it was 1832,
having previously been totally unknown over the next few decades,
it caused several hundred thousand additional deaths in five or six separate epidemics in London and elsewhere.
Cholera is a disease which is spread through sewage, contaminated drinking water and sewage contaminated food.
If you keep sewage and water apart, there's no cholera.
If you combine them, you get cholera.
The sewers of London at that time were a perfect environment for the spread of cholera because sewage went into the Thames,
drinking water was taken out of the Thames,
and therefore we got a wonderful environment for the spread of cholera and also for typhoid and typhoid, which have the same sort of ecology.
No one knew what the cause of these diseases, what it was. It was assumed that it was essentially asthmatic.
That disease of this kind was caused by vapours emerging from contaminated ground and being
breathed in and causing the disease that the there was some suspicion about about germs,
but really no knowledge about the germ, no acceptance of the germ theory of disease.
The many say it was not as daft as it seems because it was certainly the case that death rates were always higher in swampy, low lying ground.
Where were these? And the asthma could easily be imagined to be much more prevalent than that in more better ventilated areas of London,
say in Highgate in Hampstead, which is why I was so popular as places to live amongst the better off at that time and indeed since before reasons.
What the combination of demographic data and and maps managed to do was to was to show
that this could not possibly be true and that something in the water was causing cholera.
It wasn't even known what was causing it, but a purely statistical inference from demographic data plus maps.
So it had to be something in the water and that enabled the problem to be resolved.
This map on the left is Dr. John Snow's map of the cholera cases in in part of London.
In in 1854, which, of course, you couldn't get unless you had a record of the cause of death,
which of course is what Civil Registration 37 provides you with a compulsory
record of the cause of death on reasonably modern scientific medical grounds,
he was able to show that those people who were getting most likely to get cholera in this area were getting their water from a particular pump.
The famous Broadstreet pump, and there was a replica of it in in that area with a pub devoted to John Snow on the caller.
And that that was an example of demonstrating a mode of transmission of disease,
using purely statistical data without then be able to show that the microbes under under the microscope, which led up later, was responsible.
And John Snow in this particular case, and William far more broadly were able to to so demonstrate the importance of water.
Water sources in the epidemiology of cholera and typhoid imperative that several in modern terminology,
several hundred million pounds was then spent in the 90s,
in the 60s in producing a major system of interceptor sewers in London with the primary purpose of
the elementary task of separating sewage from drinking water as a consequence of that investment.
Cholera disappeared and typhoid imparato typhoid went into terminal decline.
Quite remarkable example.
And those are the sewers which still operate in London, although they're now need a considerable expansion thanks to the growth of population.
Hence the great London Project at the moment, as you would have probably heard of.
So. I must press on.
The problems of voter registration and sentences, particularly of censuses,
are leading to a radical change in the way that data are collected, which has considerable political overtones and is quite controversial.
This is the development of person no registration systems,
which would use a combination of census and administrative data to to to create the possibility of record linkage for every individual.
So individuals are traced from or tracked from birth using a unique personal number,
which is then used for their subsequent vital events for recording such vital events and also linked to to their residence,
to their tax and other things. So you can see why it may be controversial.
OK, I've got some more questions in a modern household sense that you got in front of you, something to take away in case it amuses you.
And this is a summary of what the questions are they getting rather numerous.
And that's one of the reasons why the future of the census is is under doubt.
There are all sorts of problems typically with the census.
Naturally, some people have missed as undercount mobile populations.
I know in the desert or homeless people on the streets of London are difficult to count.
Mistreatment is common. Old people exaggerate their age.
People in simple societies don't know their age. And so you get a very amusing aspect of AGP, which is illustrated here.
And this is AGP in the Indian census in 2001 when people don't know their exact age.
So it's not important to them terribly in poorer areas.
They will they will approximate it. Naturally,
they were rounded up as well as the decimal system to the nearest ten available without feeling that they were rounded up to the nearest five.
And you can see that there's a great excess of people at a different age of 10 and a similar one, a small one at age five,
which diminishes with the younger population, younger population, much better educated,
much more likely to know its exact age than older people up here.
Most of them don't know that exact age.
So that's got to be corrected by all sorts of ingenious devices if you want to have a proper population pyramid.
We also have problems in this country. The sense of 1991 was thought to to have missed a million people.
Subsequent enquiries suggested haven't actually missed a million people, but in fact, they had emigrated.
The estimation of that of that excess emigration was itself turned out to be inaccurate and require
the owners to invent a fudge of 290000 people to account for the unattributable demographic change,
a new category in population which was inserted into the census estimates to block to
for that to block the gap in the estimates of a yearly basis and the census total.
And the 2011 census showed the 2001 census to be wrong by about 250000 people as well.
So we've got a problem with the census, several reasons for having the problem.
The census. The pattern of expenditure is uneven.
Every 10 years you've got to we've got to assemble a large number of people to carry out the census enumerators,
analyse this and the other and the cost of all the publication and analysis,
about 500 million per time that actually, if you think about it, isn't all that much per head.
With a population of 60 million, it's only about 12 quid per head.
So it's not that bad. But it seems it's an awful lot in a budget when it comes in as a lump every 10 years, as it were,
rather than being spread evenly so that the cost of census is one of the reasons for for the pressure to move to something else.
You'll never get the data quicker than a year after the census. The detailed data takes two years or even more.
So there's already a picture of the past. And then when with a mobile society, it starts getting obsolescent very rapidly.
As Harold Macmillan observes, even back in nineteen fifty six,
he said that using using the census data to make rational decisions about distribution of expenditure.
And so it was rather like using last year's railway timetable to catch this year's trends.
There are increasing civil liberties objections both from the right, especially in North America and also from from the liberal left.
And there's a particular problem in Germany for obvious reasons, for any kind of enumeration,
you don't normally get more than 95 percent of the population counted.
And it may be in some districts in Britain, it was down to 62 percent, according to the estimates later, mate.
And so there are all sorts of problems about the census, which is leading to the, um,
to this kind of comment with an increasingly intrusive welfare state where governments are spending 30, 40, 50 percent of the whole GDP.
They're trying to do so on the basis of inadequate numbers. Consequently, population registers are gaining ground.
And it is now the case that a majority of countries in Western Europe have moved
away from traditional census of the kind which you've got in front of you.
And we've moved to a system of population registration whereby which is thought to include everyone in the population without being included,
in which you can't really access public services,
which has been uncontroversial for two or three decades now in the Scandinavian countries, and is being adopted very generally.
I think in the 2010 11 round of of censuses, only Britain and Spain and Portugal held traditional census.
Eastern Europe. They still have traditional censuses in Western Europe.
It is now much more question of population registers. The UK government has decided that this census you've got in front of you shall be the last.
It may have to change its mind because they have not yet come up with the replacement.
We've got to have the data to run to try and run some aspects of the country properly.
No one's yet decided, despite some frantic efforts, what should replace it.
They are nervous of a population register and in any case, there is a time between now and 2021 to create one.
It is a complicated process and I think you're cobbling together estimates of all kinds of separate, separate,
separate systems which already exist, including commercial ones, were already part of the way to register in the UK without knowing it.
We already collect data increasingly universally on all of these things.
The National Insurance number. Everyone is on a single national insurance.
No Department of Work and Pensions uses it.
Majesty's Revenue and Customs uses it.
The National Health Service Central Register also includes all births now and all people resident in the country.
And there are various other ones which which I mentioned here. These if there were to be a population because of these we put together linked by
personal number and and probably administer to local authority level as it is in in.
In the Netherlands, that's not going to happen by 2020. What exactly what will happen, though?
It'll probably be some sort of messy British mismatch.
We'll have to wait and see. So things are changing rapidly in the world of enumeration.
That's not to say without controversy. And from my own part, it seems to me the controversy is needless nonetheless is going to be, I think,
an increasingly interesting political and salient political development over the next few years.
If you can watch with some interest there, I will stop.
Thank you all very much.