Such an analysis is only as good as the variables considered.
We have proof that their projections were wildly off so I guess we can conclude they considered the wrong variables.
...the actual size of the relationship they find is about a third what the earlier authors did...
The important part of what they found was the tax incentives affected the timing of births but not the overall number in the medium to long term.
"...which would mean that an increase in tax value of child benefits of $440 would (all else held equal) get us at least back to replacement level, and $1800 at least back to our circa-1960 peak.
Wait. On the one hand you claim a multivariate analysis but the conclusions only hold if "all else held equal"?
Look, whatever they considered their conclusions simply don't hold in the real world.
We've provided much bigger tax incentives than they say are necessary and the rate hasn't improved.
Wrong; as you yourself noted earlier, your link also used more recent data.
They conclude that the relationship is "not statistically significant" using a standard approach that treats 'no relationship' as the default (null hypothesis); without that debatable assumption, the actual size of the relationship they find is about a third what the earlier authors did
The important part of what they found was the tax incentives affected the timing of births but not the overall number in the medium to long term.
That "not" is based on a debatable albeit standard assumption as to what the default conclusion is, as I noted.
which would mean that an increase in tax value of child benefits of $440 would (all else held equal) get us at least back to replacement level, and $1800 at least back to our circa-1960 peak.
Wait. On the one hand you claim a multivariate analysis but the conclusions only hold if "all else held equal"?
No contradiction there; in a multivariate analysis, the only way to see the influence of changes in a single one of those multiple variables is to hold the rest constant.
Look, whatever they considered their conclusions simply don't hold in the real world.
We've provided much bigger tax incentives than they say are necessary and the rate hasn't improved.
You keep returning to your own vomit of imposing a univariate analysis on a multivariate reality; it's ignorant and wrong no matter how often you repeat it.