Soininvaara is not a demographer

Edit 18 Noveber 2015

Some people have asked me what is wrong with using Nigeria as an example or the type of reasoning used in Soininvaara’s post. The problem is that it uses the same type of reasoning that led people in the 1970s to believe that there will be a population bomb. People looked at the fertility levels at the time, assumed they would stay constant and predicted how long it would take for the world population to double, triple, quadruple etc. However, this assumption has been proven to be invalid (fertility rates decrease when people are better off) and even UN does not provide the “constant fertility rates scenario” in its projections anymore. The mechanisms that affect population growth are complex and when projecting population growth, we must make complex assumptions based on those mechanisms. Nigeria is not a very good example of the most prevalent fertility trajectories in Sub Saharan Africa, since its fertility levels have decreased less than in most other countries of the area and thus give the wrong impression that when projecting population growth we could assume the current rates stay constant for long periods of time.

Original post

A Finnish Green Party Politician Osmo Soininvaara recently stated that the world population bomb is not over like some people claim (see here in Finnish). He based his argument in showing that in Sub Saharan Africa fertility rates (the average number of children per woman) are still high. He argued that people in for example Nigeria keep having lots of children, because religious leaders tell them to. He also noted that people in Nigeria have children in order to have someone to take care of them when they are old.

I agree with the latter point and anyone who doubts can watch Hans Rosling explain why ending poverty will lead to lower fertility rates.

When it comes to other views Soininvaara has about Sub Saharan Africa (SSA), I am not sure he thought his argument through.

First, he based his argument on the fertility rates of one country (Nigeria), which seems to be an exception rather than a rule when each SSA country is examined individually. Most countries show a downward trend in their fertility rates (see below). Moreover, basing one’s argument on one country only is hardly convincing giving the huge variation in fertility rates in the region: from 1.44 in Mauritius to 7.56 in Niger.

All Sub-Saharan African Counties (click for a better graph).

all SSA TFR

According to World Economic Forum (WEF), the most promising economies in SSA are found in Mauritius, South Africa, Rwanda, Botswana, Namibia, Kenya, Seychelles, Zambia, Gabon and Lesotho. WEF’s ranking includes measures of education, health care and infrastructure in addition to more traditional economic measures. Fertility rates have decreased markedly in all these countries, six out of ten being at around three children per woman or less, emphasising the importance of fighting poverty and providing health care and education in order to reduce fertility rates.

Top ten economies in the region (click for a better graph).

best economies SSA TFR

According to UN population projections, it is true that the world’s population will keep growing for some time still and the fastest growth is in Sub Saharan Africa. The smallest changes in fertility may cause big differences in population size a few decades later, so projecting population is a very difficult task, like the graph below, put together by the most prominent professionals in the field, shows.world population

Instead of throwing out arguments about Nigerians or anyone else not being able to “achieve” lower fertility rates due to following the instructions of their religious leaders, it would be more useful to think why fertility rates differ so drastically around the world. The important thing is to figure out how we could ensure a better future for everyone in terms of economic prosperity, health care, education and social safety nets.

Numbers don’t lie, but news do. An analysis of news coverage of polls in Finland.

Inspired by a friend’s rant in Facebook regarding the media’s way of presenting poll results and by a public lecture of Nate Silver at LSE, where similar problems were discussed, I decided to investigate the news regarding the popularity of the largest parties in Finland. I wondered, what the polls actually say about the popularity and is that reflected in the language used in the news.

I limit my mini-investigation to the four largest parties: Social-democrats (SDP), National Coalition Party a.k.a. Kokoomus (KOK), Centre Party a.k.a. Keskusta (KESK) and True Finns Party a.k.a. Perussuomalaiset (PS), because the polls usually only give the margin of error for the largest parties. Therefore, I can only try to estimate the accuracy of popularity of these parties.

I searched for a few latest polls in the two biggest news institutions’ websites in Finland: Yle.fi (the National Broadcasting Company) and HS.fi of Helsingin Sanomat (a broadsheet with the largest number of readers). In the end I chose seven polls, conducted between December 2012 and April 2013. Yle uses Taloustutkimus and HS TNS Gallup to conduct the analysis.

polls

The figure clearly shows that if we consider the margins of error reported by Yle and HS, most of these polls cannot distinguish, which one of these four parties is the most popular one. However, arriving to this conclusion is not easy due to four reasons:

  1. Margin of error is only reported for “the biggest” parties, although I couldn’t find a definition of what “the biggest parties” mean. I assume it means these four, since there is a significant gap between these and the 5th largest party popularity in all polls. In the latest HS poll (24 April 2013) the margin was not reported at all.
  2. Yle polls report that the results of the polls are “more accurate than what the margin of error would imply” due to calibration methods they use, but this is not explained further. Therefore, I chose to ignore this information here.
  3. In order to understand, what margin of error means, one has to know that it actually is a 95% confidence interval and that this interval (in simple terms) means that “we are 95% confident that the value in the total population is within this range”. In other words, if we drew an infinite number of random samples from the Finnish population and asked, which party people support, in 95/100 cases we would get an estimate within the range of 95% confidence interval. In 5/100 cases the estimate would be outside the range. The interval is reported, since as long as we don’t actually ask everyone, we cannot be entirely certain that our estimate is correct. However, we can provide information on how certain we are. Wide range implies more uncertainty than a narrow range.
  4. Most importantly: the way these polls are reported in the media is almost entirely inaccurate. I will elaborate this claim below.

The first poll (Yle 2 Dec 2012) was titled “Support for Centre Party in rapid increase“, which is not far from truth, since their popularity was 2.5%-points higher than in a previous poll and the margin of error was 1.4%-points. Therefore the overlap of the 95% confidence interval is marginal: the upper limit for the old poll’s estimate is 16.9% and the lower limit for this poll’s estimate is 16.6%. So, maybe their support actually has increased. Later they state that KOK is clearly the largest party, which is not the case, not at least clearly: looking at the figure we can see that the confidence intervals of KOK and SDP overlap. Therefore, the difference in their popularity might be only a coincidence (or noise) due to sampling. In another sample we might have gotten estimates presenting similar popularity for the two, or even higher percentages for SDP. The correct interpretation thus is: KOK is more popular than PS or KESK, but not significantly different from SDP. SDP seems to be more popular than PS but we’re not confident that there is a significant difference between PS and KESK or SDP and KESK.

The reasoning for all of the polls is similar, so I won’t present it in as much detail as above for the rest of the polls. Instead I’ll focus on the most inaccurate reports I found. If you’re interested in comparing these further, please take a look at the list of links below. As long as you have fluent Finnish skills, you should be able to do it based on this blog post.

The Centre Party is the second most popular” (HS 24 April 2013)*. Really? Looking at the figure, we quickly observe that the popularity of all four parties is really similar. We cannot even distinguish between the most and the least popular among these four — all the confidence intervals overlap. Thus, one should say: according to the latest poll, all the four biggest parties have similar levels of support.

The Centre Party is the most popular, SDP crashed” (Yle 29 April 2013). Guess what? I don’t agree with the statement. It indeed looks like KESK is more popular than SDP, but based on these results, it is impossible to say, whether it is KESK, KOK or PS, which currently is the most popular. The estimates differ only a tiny bit and the confidence intervals clearly overlap. The statement is not just exaggerating. It is false. What about SDP then, did it crash? Well, I don’t think so. The point estimate of their popularity is indeed lower than it has been in previous Yle polls in the figure. However, we have no way of knowing, if that was due to chance (remember the sampling thing!) or if there actually is a difference, since the confidence intervals overlap in all but the earliest poll in 2 December 2012. Therefore, my interpretation of this poll is: there is little difference in popularity of KESK, KOK and PS, whereas SDP may be less popular than the three other parties and also less popular than it was in the beginning of December 2012.

Okay, the rest of the interpretations you have to conduct yourself. I’m left wondering, why false information is so commonly presented in the media. Is it due to lack of understanding of statistics? Or maybe due to a belief that people are not interested in news, which do not rank the parties? Would it be so bad to truthfully say that we don’t know, which party among certain candidates currently is the most popular? I cannot think of a reason, which justifies false statements, when the journalist clearly should know better.

* If there’s anything lost in translation, blame me, I was the one, who translated these from Finnish to English.

Links to original news articles

Margins of error:

  • Yle 2 Dec ±1.4%-points
  • Yle 30 Dec ±2%-points
  • Yle 8 Mar ±1.3%-points
  • Yle 29 Apr ±1.4%-points
  • HS 23 Jan ±”less than 2″%-points –> I assumed 1.9%-points
  • HS 27 Mar ±”less than 2″%-points –> I assumed 1.9%-points
  • HS 24 Apr not reported –> I assumed 1.9%-points

How research becomes populism – Abortion debate in the Finnish Parliament

Liberal abortion legislation was introduced in Finland in 1970. Every now and then, there is discussion regarding, whether the law should be changed in any way. Some would like to see a day, when abortion is available on request (as in Sweden for instance) and others wish to make it more difficult to obtain abortions.

Recently, a few members of parliament from the Christian party, the Centre party and the True Finns party suggested that the legislation should be changed  so that medical doctors and other hospital personnel should be given a right to refuse performing abortions, if that’s against their conviction.

Last Thursday, the parliament discussed the suggestion. Quite rapidly the discussion shifted from the rights of hospital staff into whether abortions are morally justified. An MP from the True Finns party, Mika Niikko, referred to a study showing that more than 50 percent of the women, who went through a termination of pregnancy were depressed a year after the termination and that two percent suffered from severe depression. Later he tells that the study was conducted by “a researcher called Söderberg” and also mentions that there is a Finnish study by Gissler, Hemminki and Lönnqvist that found the risk of suicide being three times higher for women, who had had an abortion, compared to the women, who had a childbirth.

Given that I have worked on abortion-related topics for a while, the results of the studies seemed somewhat surprising to me and I decided to track down these papers. Since the citations are not more specific than what I’ve described above, I cannot be sure I found the right papers, but I managed to identify two, which fit the criteria (Söderberg et al.; Gissler et al.). After having looked at the results of these studies, I have to say I’m quite concerned about the relationship between academic research and policy making.

The paper by Söderberg and colleagues is a study of 854 women, who had had an abortion in Malmö, Sweden in 1989. The researchers identified a case group of 139 women that had experienced emotional distress and doubts regarding abortion decision and compared them to a control group of 114 women not having these feelings. Given that I only have access to an not-so-clearly-written abstract rather than a full text, I cannot say much about the study design, but the conclusions of the study are clear: the researchers identified risk factors of experiencing emotional distress (such as poor support from family and friends and underlying ambivalent attitude to abortion) and state “[t]he risk factors identified suggest that it may be possible to ameliorate or even prevent such distress”.

The other study compared suicides after pregnancy in Finland between 1987 and 1994. The researchers were able to identify 73 suicides within one year after the end of the 667,572 pregnancies observed during the study period. Women, whose pregnancy had ended in abortion, were six times more likely to commit a suicide than women, who had a childbirth. The researchers state clearly at the end of the paper that the study was not able to study causality between these two events, because they had no information of pre-pregnancy mental health conditions of the women. Thus, the causal relationship could go either way: suicides and abortions are caused by similar things or abortions cause mental health problems to some women. In addition, I’d bear in mind the small number of suicides observed, which adds uncertainty to any conclusions.

Had Niikko read a more recent paper from Gissler and colleagues, he would have discovered that having mental health problems is associated with a higher risk of abortion. Therefore it seems like experiencing difficult life events is associated with higher risk of abortion rather than the other way around. Also this paper ends with caution: more research is needed, before claiming causality in this complex relationship. Many previous studies have suffered from severe problems in research design and thus cannot be trusted.

So, the studies Niikko referred to were from late 1980s and early 1990s. It goes without saying that they are old and that there are more recent studies he could have referred to. Moreover, the results of the studies were clearly misinterpreted. The really sad part is that in the discussion Niikko was the only MP, who even tried to refer to academic studies to justify his point of view.

Where are the policy implications of policy relevant academic studies hiding?