BMI variables in the youth panel - potential errors?
I've come across something strange with the BMI data in the youth panel (available in waves b, d and f). The limits of ypbmi_dv are around 8 and 90, in each wave the data are available. A BMI of 8 (or 90!) would be impossible, so I went back to the height and weight data, and have found that there are BMI values present even when there is no reported height and weight. The only coding is -9 for missing; there is no 'wildcard' option.
Furthermore, even for rows where height and weight are reported, BMI is not consistent e.g. a respondent with a BMI of 9.8 is 157cm tall and 41.3kg - by the standard BMI calculation, this respondent's BMI should be 16.7. I've done a few more spot checks and can't unpick what's going on with the BMI variable. Can you shed any light on this situation?
It's quite urgent I'm afraid - I work for the Department of Health and Social Care, and this task is part of a high priority workstream on inequalities in childhood obesity. I'd be really grateful if you could help!