I’ve been sitting on “A Farewell to Alms” for a few days after seeing a footnoted claim that I knew I’d have to look into and most likely write a post on. The note is in chapter 14 where Clark writes “And now the rich in England have fewer children than the poor, so if children are to be counted a blessing and not a burden the advantage now lies with the poor (though in some other advanced economies there is no difference between rich and poor in this respect).19” From the accounts I had usually heard, the demographic transition was supposed to be a universal phenomenon and that would over time engulf even the currently developing world. So what is Clark citing? Nicola Dickmann, 2003. “Fertility and Family Income on the Move: An International Comparison over 20 Years.” Dickmann acknowledges that lower income families did have more children back in the 80s, but this gap seems to have narrowed in more recent years. I should note that her method was to look at data for married couples (completely ignoring single mothers) within a certain age range in the USA, Germany, Canada, U.K, Finland and Sweden. The correlation between income and family size (and statistical significance) was generally small. It was positive in the last two and negative in the rest. I wouldn’t say it completely upends conventional wisdom, but it’s definitely something to consider. Two relevant EconLog posts are The Decline of the Rabbit Strategy and Kids, Opera, and Local Status. A recent OB post somewhat relevant, Humans Are Evolving. A lot of people may not bother clicking through to read the pdf, so tomorrow I think I’ll copy some of the tables into html below. UPDATE: Transcribing all the data got to be a chore, so I’ll just put up some images. The rules for transforming the text I can copy is pretty simple so next weekend if I’m not busy I’ll try to learn python and then replace it with html. UPDATE2: Done. I couldn’t completely automate everything. I’ll put up the code in a later post.

Some unrelated notes. For anyone wondering when I’ll start twittering, don’t hold your breath. I never update my facebook status (or bother logging on most of the time) because nothing happens worth talking about. If I have something to say, I’ll blog it. Maybe if I read twitter my eyes would open up to the possibilities, but I don’t. Also, Against Politics once hosted Richard A. Garner’s “If Hobbes Is Right, Then He Is Wrong”. After the site went down, google only turned up other sites giving that bad link. After bugging Aschwin about it, he restored it. Enjoy.

Average number of children per woman and income level USA
1979
West
Germany
1981
Canada
1981
UK
1979
Sweden
1981
Finland
1987
Less than 5.000 int. Dollar 2,56 2,00 2,11 1,88 2,00
5.000 up to 10.000 1,96 2,00 2,07 2,14 1,83 2,00
10.000 up to 15.000 2,18 0,78 2,12 2,01 1,74 2,00
15.000 up to 20.000 2,11 1,14 2,04 1,84 1,86 1,27
20.000 up to 25.000 1,91 1,48 1,99 1,98 1,98 0,28
25.000 up to 30.000 2,00 1,77 1,86 1,69 2,00 1,00
30.000 up to 35.000 1,78 1,74 1,87 2,17 2,33 1,21
35.000 up to 40.000 1,96 1,83 1,65 1,71 1,51
40.000 up to 45.000 1,73 1,59 1,65 1,50 1,02
45.000 up to 50.000 2,10 1,43 1,73 2,50 1,67
50.000 up to 55.000 2,31 1,69 1,56 1,33 1,40
55.000 up to 60.000 1,33 1,67 2,75 1,50 1,26
60.000 up to 65.000 3,00 1,81 2,14 2,00 1,12
65.000 up to 70.000 2,61 1,24 1,25 2,00 1,29
70.000 up to 75.000 0,00 1,68 0,75 0,00 1,16
More than 75.000 3,00 1,88 2,43 2,50 1,61
Statistical interpretation
Variance 0,49 0,25 0,21 0,34 0,04 0,20
Standard deviation 0,70 0,50 0,46 0,59 0,19 0,44
Maximum difference 1,67 1,22 2,00 1,17 0,60 1,72
Mean 2,03 1,48 1,87 1,81 1,95 1,36
TFR of elicitation year 1,81 1,43 1,70 1,82 1,63 1,59
Correlation Income – Fertility
Significance 0,002** 0,764 0,000*** 0,059 0,241 0,000***
Correlation coefficient -0,064 0,012 -0,102 -0,051 0,024 0,077
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