01385nam a2200169 a 4500 20260901030415.0 250101s2019 xx o 000 0 eng d Liying Luo Constraints in Random Effects Age-Period-Cohort Models arXiv 2019 text online resource Random effects (RE) models have been widely used to study the contextual effects of structures such as neighborhood or school. The RE approach has recently been applied to age-period-cohort (APC) models that are unidentified because the predictors are exactly linearly dependent. However, it has not been fully understood how the RE specification identifies these otherwise unidentified APC models. We address this challenge by first making explicit that RE-APC models have greater -- not less -- rank deficiency than the traditional fixed-effects model, followed by two empirical examples. We then provide intuition and a mathematical proof to explain that for APC models with one RE, treating one effect as an RE is equivalent to constraining the estimates of that effect's linear component and the random intercept to be zero. For APC models with two RE's, the effective constraints implied by the Open access — freely available to read. https://arxiv.org/pdf/1904.07672v1 Read the full paper (PDF) ERES 714 714 0 0 0 3 GEN MAIN MAIN SCICOMP 2026-09-01 0 YGE000975 2026-09-01 03:04:16 https://arxiv.org/pdf/1904.07672v1 2026-09-01 PAPER