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→Which day is it?
Not only can are the boundaries of days problematic: For activities which typically span across day-boundaries, one might take different approaches regarding to which day the data should be associated. Tracking sleep is a typical example of this: If you go to sleep before midnight on day X and wake up on day X+1, for which date do you want to associate the summary statistics of your night's sleep?
Not only can are the boundaries of days problematic: For activities which typically span across day-boundaries, one might take different approaches regarding to which day the data should be associated. Tracking sleep is a typical example of this: If you go to sleep before midnight on day X and wake up on day X+1, for which date do you want to associate the summary statistics of your night's sleep?
Some tools (e.g. Fitbit) will choose day X as the day to associate the sleep (interestingly this might even happen if you go to sleep after midnight when it objectively is already day X+1). Other tools (e.g. the Oura Ring) will choose day X+1 as the day for the sleep summary statistics, i.e. the day on which you wake up. It can be important to understand this distinction both when comparing different sleep metrics to each other, in order to compare data from the correct dates but also when trying to understand how sleep might affect other variables. Not understanding for which day the sleep is recorded can easily result in being off-by-one.
Some tools (e.g. Fitbit) will choose day X+1 as the day to associate the sleep, i.e. the day on which you wake up. Other tools (e.g. the Oura Ring) will choose day X as the day for the sleep summary statistics, i.e. the day you went to sleep (Interestingly this even happens if you go to sleep ''after'' midnight).
It can be important to understand this distinction both when comparing different sleep metrics to each other, in order to compare data from the correct dates but also when trying to understand how sleep might affect other variables. Not understanding for which day the sleep is recorded can easily result in being off-by-one.