How tall am I again? A longitudinal analysis of the reliability of self-reported height.

Self-reported height measures are increasingly being included in large-scale surveys in order to measure BMI. There have been concerns about the validity of self-reported measures but there remains little understanding of why respondents may not give accurate height reports. We examine whether a lack of knowledge could be a contributing factor, by investigating the reliability of self-reported height over time and across countries. We use longitudinal data from four large-scale longitudinal surveys conducted in Australia, United States, United Kingdom, and Europe (14 countries) where survey respondents were asked to report their height over multiple time periods to measure the extent of consistency of height reports across time. The overall level of inconsistent reporting of height is largest in Australia and Europe. Individuals with lower levels of education were significantly more likely to give two height reports that differed by 5 cm or more. Across all countries, inconsistent reporting with large height differences between waves was also more common among those in older populations. The findings point to subgroups of the population exhibiting a lack of knowledge regarding their own height.