Assistant Professor of Medicine at Icahn School of Medicine at Mount Sinai. Applied Mathematician with research interests in signal/image processing of sleep.
New York, NY, USA
If I'm not mistaken, there seems to be a discrepancy between total sleep time variables in SHHS data (Visit1). The variable slp_time appears to be accurately calculated, however the variable slptime appears incorrect. As an example time in bed for subject 205804 is 397.5 minutes, however, total sleep time as per slptime is 557 mins, which is longer than time in bed. On the other hand, slp_time=357 appears accurate. Cross-checking the times based on the hypnograms, slp_time appears to be the accurate variable.
EDIT: It appears there is another variable SlpPrdP, which is similar to slp_time and accurate.
Ankit Parekh, PhD.