Tempo Effects and their Relevance in Demographic Analysis

Abstract

Demographic period indicators like the total fertility rate or life expectancy are well known since more than a century and until recently there were only minor discussions about their usefulness. This changed with a series of publications by Bongaarts and Feeney (BF) in which they claimed that these indicators are inappropriate for describing current demographic conditions when the average age at childbearing respective death is changing. Therefore, BF proposed alternative tempo-adjusted indicators for such situations which can be very useful for demographic analysis. The still existing scepticism against the BF approach and the general rejection of mortality tempo adjustment in particular have their origin in a set of misunderstandings and misinterpretations of tempo-adjusted indicators. This paper systematically describes the basic idea of tempo effects, how they can distort the commonly used conventional period indicators and how the proposed methods approximate the idea of tempo adjustment, illustrated with empirical data for West Germany. We also summarize the critiques against tempo adjustment and try to put the tempo approach in the right perspective. Finally, the paper strives for providing a better understanding when tempo-adjusted measures should be used as alternative or in addition to the commonly used conventional demographic indicators.