Tuesday, May 16, 2006

NSCB - Intellectually and Graphically Dishonest?

UPDATE: Hat Tip to the Econblogger for a comment that inspired a new plot of the data. I decided to look at a "High Series" projection of the population growth rate in the 2005-2040 time period in order to compare its fit to the widely publicized "Medium Series" from the National Statistics Coordination Board, who use a formula based on mortality, fertility and migration data. Here all I did was multiply NSCB's published projections by 110%, yielding a very curious and neat 1.0% at 2040 and plotted this against the NSCB's "Medium Series." I think my "High Series" projection "fits" better the "continuity and differentiability" criteria. (Click to Magnify)
THE SMOKING GUN: I dug up the historical data on Population Growth Rate up to year 2000 and graphed it along with the NSCB's recent projections. Mathematically speaking any reasonable "projection" of a time series like the total population of a country, or its first derivative, the growth rate, should display "continuity" and "smoothness" at the point where the historical data is joined to the projection. The plot below shows the two sets of data: First, in blue, are the population growth rates (in percent per year) based on actual census data collected at various times between 1903 and 2000 (the last census). The data comes from this October 2002 National Statistics Report. Second, in purple, are the recent PROJECTED population growth rates from 2005 to 2040 published here by the 2006 National Statistics Coordination Board (renamed from NSO).

Apart from the discontinuous and unsmooth fit of the projected data to the historical data at Year 2005, there is also a key piece of empirical data that is unknown: What was the total population of the Philippines in year 2005?? Without this data point, virtually any projection could be justified for the period following 2005. But I made this plot after wondering why the heavy use of tables of numbers by NSCB's supporting details, then just popping up this statement in the covering Press Release:
The population is projected to grow by 1.95 percent in the 2005-2010 period, from 85.3 million in 2005 to 94.0 million in 2010.
A picture -- or an accurately drawn graph -- is worth a thousand words and numerical tables. The graph of the historical data together with the NSCB's current projections, suggest to me a "discontinuous" and "unsmooth" joining of the empirical and the prospective. Remember that the three data points at 1990, 1995 and 2000 are derived from the census data. Looking at that part of the population growth rate plot above, one gets the distinct impression that in that decade of the 90s, the population growth rate was in a shallow plateau just below 2.4% and had turned upward (with a positive slope) between 1995 and 2000. Yet the entire set of projected data have negative slope. This is what I mean by the unsmooth joining of projected data to the historical data.

Therefore, I agree with Congressman Neric Acosta. What the NSCB and the government are doing here is intellectually dishonest. Data projections like this could be used to justify the government's inaction on population explosion. In fact I would add that these NSCB projections are likely to be mathematically dishonest, because as any freshman student in Calculus knows, you can spot such dishonesty with the naked eye of mathematical aesthetics. I also caught my old friend from Harvard, Dr. Cory Raymundo and Prof. Ernie Pernia both of the University of the Philippines, talking to Ces Drilon, Monday night about this projection and how unbelievable it is, considering the government has in fact abandoned the use of legally and medically accepted forms of contraception and birth control during the 2001-2010 period. Now, by comparing the historical trend as shown above, I can say with some certainty that there is something mighty peculiar about NSCB's projections. It's almsot as if they decided to ignore the results of the 1990, 1995 and 2000 census count and draw a straight line from the 80s all the way to middle of the 21st Century. It's pretty obvious that this lil bit of prestidigitation with the numbers, means that the Palace can now make a self-serving but dangerous assertion: that population growth rates are trending down despite abandoning its support for serious birth control methods and effective family planning programs, apart from Catholic Church approved natural methods such as "Vatican Roulette." If it has been fudged for that purpose, and is inexplicably discontinuous from the 10 to 15 year trend of a plateau near 2.3% or so, this will result in a serious understimation of how many citizens the government should plan for in the first half of this century. It would be insanely irresponsble if that were the case.

MY FEARFUL PROJECTION: Looking just at the historical data, especially the post WW2 era, one notes that in the 60s and 70s the population growth rate was near 3%. I think this boom in the 60s and 70s is producing an "echo" in the 90s and 00s as their progeny begin to have children of their own! We may already be seeing the beginning of that echo in the uptick between 1995 and 2000. Only the data point at year 2005 would settle which projection is closer to reality, mine or NSCB's. It is crucially important for fiscal and economic planning reasons that the projection be accurate and reliable. I actually wish NSCB were right and that the discontinuity is due to some other very special factors like changes in migration patterns. But I can't see it even in the supporting details at NSCB.

ERROR ANALYSIS: When Ces Drilon asked an NSCB Director Abejo what the "margin of error" was for the NSCB data she was at a loss to answer. The reason of course is that the set of historical data, while collected using surveys, does not rely on random sampling techniques like the SWS and Pulse Asia Surveys. They are calculated based on the change in population between census years (about every five years). Theoretically therefore, there is no "statistical sampling error" associated with population data, like the plus or minus 3% in a 1200 respondent SWS survey, because a census is meant to count every single member of the population. But there are certainly errors of other kinds, such as errors in counting and reporting how many people live in a given household; clerical errors; and the inadvertent overcounting, undercounting, even double counting or not counting that occurs during a census. These error quantities are unknown--they are unlike the statistcal error in an SWS survey (which of course also suffers from them!) which can be calculated from the random sample size. These are empirical errors. As for the Projected Data portion of my plot, it has its own statistical and systematic errors that have to be analysed in detail: errors associated with estimating the components of Population Growth, namely, fertility rates, mortality rates and mirgration patterns.

In the projected portion of the plot above, one will notice the nearly perfect linear character of the projected curve of population growth rate. This is the signature of an artificial process--the wishful thinking of Palace Spin Meisters, if you will. The slope and behavior of the curve depends entirely on the assumptions that have been made regarding the fertility, mortality and migration rates. Such projects should be continuously validated by actual census measurements, otherwise, a great historical disservice will have been done by statisticians to the nation's generations yet unborn.

For a scientific, sociological perspective on the problem of population growth, I still highly recommend to Philippine Commentary readers a careful and complete perusal of Garret Hardin's 1968 classic, The Tragedy of the Commons.

23 comments:

Jon Mariano said...

The administration is painting itself in a good light. They try to magnify the good things, and try to minimize the bad.

A very high growth rate in population is a negative, so it must be dusted under the carpet. Thanks for your neat presentation!

manuelbuencamino said...

well, Ms. Pangit herself said there were two philippines, hers and ours.

I guess the NSCB was counting the decline in population growth in Ms. Pangit's Philippines and not our Philippines.

That's to be expected. But they should have used polls instead of census reports to show that decline.

HILLBLOGGER said...

Dean,

I don't believe govt statistics - they've always doctored their stats.

In any case, there is no way the snail-paced Philippine economy could even be sustained with a rabbit-like production by the population in the country.

The only way to prevent that they eat each other is by OPEN FAMILY PLANNING. It's virtual murder for children to allow poor, hungry, uneducated folks to divide and mulitply and to keep making more children that they could afford at will when it is so easy for the State to "educate" them by giving them the tools to prevent that from happening!

It's been done before no less than by Imeldific!

Punggok's sense of values are absolutely upside down! She's one Catolico inutile!

Rizalist said...

These small numbers and seemingly minor differences are gonna bite us in the neck sooner or later. These are the kind of things that have long lasting deleterious effects over decades of a nation's life.

HILLBLOGGER said...

Dean,

Why is NSCB being intellectually dishonest? They are, most likely, following a Palace guideline - "positivize" the figures which is highly plausible.

The stats gathered by national census could also be very flawed for all we know - is it wrong at all to assume that there tens and thousands of kids out there in the squatter areas which were never registered at birth nor afterwards...

Gloria is beind outrageously demonic - the priority today is to put funds towards an education program designed at providing accessible, free advice and birth control paraphernalia to every single family.

Why is Gloria REALLY against instituting such family planning centers and going all out for birth control? If she is afraid of the Church, then she can change the title of the blasted family planning or birth control education to something like Responsible parenthood crap of some kind!

She and her government are committing "murder" by proxy on children of poor, impoverished, uneducated families become malnuorished, unehalthy, cannot survive and die just because our stupid government has "moral" qualms about instituting draconian measures as family planning and birth control.

Where is morality in all that?

Gloria must be told that her place in heaven is not assured anyway much as she tries to toe the Church line concerning birth control, etc. Why? Her Creator is bound to ask her why she allowed
murder by proxy to be committed on helpless, innocent children when it could have been prevented...

If she really feels it's a sin to encourage her countrymen to use birth control devices or to avail themselves of needed family planning tools, she need not fear the wrath of heaven! As a Catolico inutile, er cerrado, she can always resort to the sacrament of the dying before her ultimo adios!

Or is she hell bent on closing her eyes to the population explosion because - gee whiz - more babies mean more people to export to uncharterred waters and unknown territories around the globe so that they can send 13billion dollars MORE annually to keept her dastardly government afloat?

LCsiao said...

That kind of distorted thinking, as evidenced by Gloria's cabal of thugs, was precisely what a GCF (Greenhills Christian Fellowship) pastor by the name of Dr. Luis Pantoja, Jr. showed before his congregation of elite churchgoers in defense of Gloria's debt binge (in his capacity as a 1st rate Gloria apologist cum minister).

My jaw dropped when he uttered way back in 2003 that the debt problem under Arroyo isn't that big a deal since, he reasoned, we are an overpopulated country, the debt burden can be properly shouldered by more people (!!!!!)

Mind you, he wasn't joking. And to make things worse, his mindless audience seemed to agree.

It just shows us how depraved some people can go just to support their untenable positions.

Some twist their sermons while others outrightly prostitute gov't data by resorting to all sorts of
mathematical shenanigans.

Such is the fate of those who choose to relinquish truth to serve Gloria as their god.

Econblogger said...

DJB,

May I respectfully point out a serious problem with your objection. The official population projections are not the outcome of a curve fitting exercise on historical data. Based on the official method, the objection of discontinuity and non-differentiability are misplaced. The official method also prevents just any population projection to prevail for 2005.

The official method is described in some detail here (please follow link to the PDF file for more technical information). The projections are based on extrapolations regarding fertility and mortality rates. The base data is the 2000 Census, combined with information from the 2003 National Demographic Health Survey, the 2000 Family Planning Survey, and the 1995 Census (to construct life expectancy estimates).

In the absence of a detailed peer review, I am unable to judge whether the method was properly applied. I believe however the method is fairly conventional, by UN standards. I find no reason to attribute venality or even incompetence to these projections. I do however think that some idiot decided to sensationalize the finding, which was picked up by our ever-reliably-stupid press.

Rizalist said...

Econblogger,
Got most of that from the NSCB supporting details. As you point out the projected data are not derived from a fit to the historical data but represent a particular choice ("the Medium Series") of assumptions and consequences.

My application of continuity and differentiability criteria is valid for deciding WHICH of the three possible outcomes, for which NSCB had parameters and data (Low, Medium, High), fits the historical data better.

My guess is that these are roughly three parallel curves with the low and high assumptions above the one they actually drew.

But probably the HIGH Series would fulfill the continuity and differentiability reqmts better.

I didn't mean to imply that they merely extrapolated the historical data. ONly that a properly selected projection would fulfill those criteria better.

Hope I explained that okay?

BTW note that by selecting the medium series, they really forcing a negative slope at 2005, when the previous slope was positive! Something fairly dramatic had to have happened between 2000 and 2005. But nothing did. All they did was choose the medium series.

Rizalist said...

Econblogger, Thanks for the link. They explained the methodology in 7annex.pdf (with all the tables) involving fertility, mortality and migration. I would've been more impressed if they showed all three data sets in the plot with historical data to see which of them fit better...

maybe i'll make a new plot with low, medium and high series assumptions...

thanks, roehl

ellen said...

Talking of numbers, I understand Dean, that Belinda Cunanan quoted you on Sigaw ng Bayan's illusionary 9 million signatures.

Isn't that something?

Rizalist said...

Hi ellen, No i think she was quoting our regular commenter, the Hillblogger.

Karl M. Garcia said...

If future historians make an analysis based from the nso and nscb then the saying let history be the judge would not be reliable.

The nscb is a redundancy of nso,because aside from nso,what other group does it coordinate with?

on cunanan:Go Anna!

Karl M. Garcia said...

Sigh! Ms. Cunanan,I would not have said anything against you because I respect you as a wife of General Buddy Cunanan, a former long time neighbor in camp aguinaldo and the mother of my nursery school classmate.

pero Ma'am lumulusot pa kayo eh,you should hav believed your daughter that it is improbable.

Karl M. Garcia said...

going back to NSo,

if they manage to screw uo the import export data of the port of manila alone by not updating their software to synchronize with custom's software.I happen to know this because I coordinated with the NSo regarding South harbor's inward foreign manifests and they asked assistance to the IT dept of a private company(a port operator and fromer employer) to assist them in reconciling their data with the bureau of customs' data.and that is only for the port of manila,gosh there are dozens of more ports to reconcile data.

With the kind of inter agency miscoordination here in the pinas
how can we rely on the coordination skills of the nscb?

Karl M. Garcia said...

Our current economic indicators are already screwed up due to the comedy of errors that begins with the nSO....

The nEDA gets their data from nscb
and only bothers to go directly to the source if someone notices it.

If only our interagencies have a shared data base, we might not even need a coordinating board .

Rizalist said...

Karl,
Perhaps the use of the word DISHONESTY was a bit harsh on my part because I am sure the scientist-statisticians over there only do what they are told. They do the science, someone else decides on politics

Karl M. Garcia said...

I have to agree DJB!

As in any agency they only do what they are told.

Karl M. Garcia said...

And there is always ,GARBAGE IN GARBAGE OUT!

the statisticians only analyze by the data given them by the data gatherers.

Rizalist said...

You are right of course about gigo. but we shouldn't denigrate the true professionals at NSCB who probably know all I've said here and more are true, but suffer in silence. I can't believe anyone who has devoted themselves to a technical profession would INTENTIONALLY falsify data. It's just that statistics does leave a lot of room for interpretation and uhmm, prevarication.

As I said however, these seemingly small numbers will have momentous weight in planning and resource allocation...getting them wrong now means that generations will pay for it..

Karl M. Garcia said...

Amen to that!
Damn Straight!

HILLBLOGGER said...

Dean,

So, what really is the population count of the Philippines as of 2005?

Karl,

Thanks for the encouragement. You realize that Brig Gen Cunanan (or Maj Gen) currently sits on several boards of sequestered corporations? I wonder if he's still the chairman or prez-ceo of PNOC, one of the most lucrative posts?

This is the reason why Bel Ol Cun will do anything, distort facts, make sabunot to those who wish to "harm" her beloved Punggok!

Econblogger said...

Rizalist,

My recent post here essentially agrees with your update. Thanks for calling attention to this important subject!

Rizalist said...

HB, I read somewhere that we are supposed to have a census every 5 years but I didn't hear of one from last year. Also it is the first and most crucial point in the projection.

Econblogger: yes, it IS a very impt topic and one where SMALL numbers are deceptively so. Somewhere in NSCB there exists honest and professional people who have information that in more normal societies would be taken and used with the utmost seriousness by the policy makers.

Perhaps the govt didn't have the money to do a census, but all the more reason to use mathematical techniques to make up for our financial weaknesses. There's a lot that "aesthetic" can do that even empirical data cannot.