This chapter serves as a methodological warning for the entire book: we demonstrate that it is the turning points that in fact play the most important role in demographic trends. We first discuss external migration, where the contrast between past and future is most
glaring, and then show that the same holds true for the fertility trend, but with latencies and lags that are often lengthy. We close with a remarkable example of a turning point in the trend in age‐specific mortality, to conclude that demographic trends cannot
be extrapolated directly, but only explored through forward‐looking scenarios incorporating political and economic factors.