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I have seen this episode about religion from the documentary series "Through the Wormhole" and how it is disappearing and they say that it will have only 10% theists in New Zealand by 2050. Is this true?

You can view the documentary on YouTube and they discuss the subject at about the 23 minute mark.

Oddthinking
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Derfder
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  • Please remember: Edit wars aren't a helpful way of resolving a dispute. I will lock the question if it continues. – Oddthinking Apr 21 '14 at 02:24
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    This question appears to be off-topic because it is about predicting the future. – Flimzy Apr 21 '14 at 16:58
  • @Flimzy It's definitely boarder-line. Maybe a rephrase to address the extrapolation that is being done? – rjzii Apr 21 '14 at 20:19
  • @Derfder if you are feeling unjustly censored by the moderator team please take your complaints to the [community team](http://skeptics.stackexchange.com/contact) instead of using comments. – Sklivvz Apr 22 '14 at 10:20

1 Answers1

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It is likely that they did a simple projection of the current trends into the future to make this prediction. On the regular census that the New Zealand Government runs, they ask each citizen what their religious affiliation is. Here are the results for the last four censuses.

Religions affiliations in New Zealand

As you can see, the answer "No religion" is trending upwards at around 10% per decade. Christianity is trending downwards at about the same rate. The total of the categories "No religion", "Object to answering" and "Not stated" is at around 50% of the population in New Zealand. Christianity makes up about 43% of the total population in New Zealand.

If the rates stay constant, we would expect that after 36 years, the percentage of Christians in New Zealand will have dropped by 36% which would leave 8% of the population left as Christians. The same would be true for the No Religion group in the reverse direction, going up by 36% to 74%.

The percentage of non-Christian religions has been growing over the last four censuses, however the rate of change is smaller than the other two groups. At about 2% per decade, by 2050 they would make up 13% of the population, outnumbering Christians.

From this simple projection, they along with the "Object to answering" and "Not stated" groups would make up the remainder of the population.

This is a simple projection from existing trends and is not highly likely to be precisely correct however it does suggest that the prediction of less than 10% religious by 2050 is close to what we should expect.

We can get a more accurate picture by looking at the breakdown of Atheists by age.

Atheists by age in New Zealand

This chart suggests that the percentage of the No Religion group in the younger population is greater than in the overall population. As they get older, you would expect the overall population to more closely match what we see in the younger population now. This is the chart from 2006 but the chart from the 2013 census shows a similar pattern.

The future is difficult to predict which is why we tend to avoid it here at Skeptics. These trends show what will happen if the forces at work do not change and the rates stay constant. Predicting for certain that the rates will stay constant until 2050 is beyond the abilities of science.

Ladadadada
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    Actually I think the graph instead represents theists being more likely to live to age 85+ ;) – Kenshin Apr 20 '14 at 03:21
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    -1 To call phrasing issues to your attention. "No Religion" doesn't mean Atheist unless you can document that it means exactly that for these surveys. In a lot of cases it just means that you don't subscribe to one of the organized religious. So you really shouldn't be saying atheist so often since someone that is agnostic is also considered non-religious and there are a lot of other situations where someone could say "Not Religious". So someone can be theistic and still put "Non Religious" on the survey. – rjzii Apr 20 '14 at 14:27
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    @rob [Enough residents of New Zealand wrote down "Jedi" in 2001 for it to be the second largest religion after Christianity](https://en.wikipedia.org/wiki/Jedi_census_phenomenon#New_Zealand). What you have said is *technically* possible but I would say needlessly nit-picky. Still, that is your right. – Ladadadada Apr 20 '14 at 16:12
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    @Ladadadada In most cases I would likely just roll my eyes and not really worry about it, but since this site strives for scientific accuracy, the correct phrasing is important. Also, with regards to the second graph, where did you get those figures from? There doesn't seem to be a link back to the raw data in your answer. – rjzii Apr 21 '14 at 12:12
  • @rob Good point, references added. The graphs come directly from the NZ census website. – Ladadadada Apr 21 '14 at 16:27
  • @Ladadadada Great! That age distribution graph is weird since I never quite trust the responses for the under 25 cohort since when you are young someone is answering for you (i.e. 0 - 4) and as you get older you might convert for various reasons. It will be interesting to see how things develop. – rjzii Apr 21 '14 at 16:34
  • @rob Which is well represented by the graph - those under-15 y.o. seem to be identical to their 20-40 y.o. parents. Also, there is "other" option for smaller religions, which is clearly distinct from "no religion", so there shouldn't be any mix-up here. – sashkello Apr 21 '14 at 23:00
  • This is a pretty good answer and shows that the claim is an accurate linear extrapolation from reasonable data. But to my mind, the real weakness of the claim is in using the linear extrapolation model in the first place - I think we should subject their choice of model to higher scrutiny. This answer says that the extrapolated figure is "close to what we should expect" but offers no evidence to support that assertion. – Nate Eldredge Jun 10 '15 at 17:01
  • For instance, the same logic would suggest that by 2086, 110% of the population of New Zealand will be non-religious. This absurdity shows that we must think carefully before accepting the linear model (or any other). Also obligatory: https://xkcd.com/605/ – Nate Eldredge Jun 10 '15 at 17:05