Heterogeneous Income Profiles and Lifecycle Bias in Intergenerational Mobility Estimation

Martin Nybom, Jan Stuhler

The Journal of Human Resources · 2016 · 142 citations · 33 references

Concepts

TL;DR

Short income snapshots used in intergenerational mobility studies can introduce lifecycle bias when they fail to reflect lifetime outcomes. The study uses extensive Swedish income data to demonstrate the magnitude of lifecycle bias and evaluate strategies to mitigate it. The authors analyze long Swedish income series and extend the errors‑in‑variables model to reduce lifecycle bias. Lifecycle bias is minimized when incomes are measured near midlife, but the model cannot predict the optimal age or eliminate bias at other ages.

Abstract

Abstract Using short snapshots of income in intergenerational mobility estimation causes "lifecycle bias" if the snapshots cannot mimic lifetime outcomes. We use uniquely long series of Swedish income data to show that this bias is large and to examine current strategies to reduce it. We confirm that lifecycle bias is smallest when incomes are measured around midlife, a central implication from a widely adopted generalization of the classical errors-in-variables model. However, the model cannot predict the ideal age of measurement or eliminate lifecycle bias at other ages. We illustrate how extensions of this model can reduce the bias further.

References

33