On average, childless women observed by the Panel Study of Income Dynamics report that they intend to have more children than they actually have. A collection of intentions that record only whether respondents intend to have another child can more accurately predict the number of children they have. Errors in the formation of intentions are not required to explain this finding. Rather, if intentions record a survey respondent's most likely predicted number of children, then the average of these intentions does not necessarily equal average actual fertility, even if intentions are formed using rational expectations.

中文翻译：

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利用意图预测生育能力

平均而言，收入动态小组研究观察到的无子女妇女表示，她们打算生育的孩子数量比实际拥有的孩子数量要多。仅记录受访者是否打算再生一个孩子的意图集合可以更准确地预测他们拥有的孩子数量。解释这一发现并不需要意图形成中的错误。相反，如果意图记录了调查受访者最有可能预测的孩子数量，那么这些意图的平均值不一定等于平均实际生育率，即使意图是使用理性预期形成的。