A number of people have asked whether the weekday effect might be explained by weekend recoveries. This is a good question. The idea is that patients might have booked the appointment in the previous week, but then felt better by Monday and so did not turn up. We wondered if this might explain the reported pattern when we first saw it in the General Practice (family doctor) data. To check, we went on to analyse 4.5 million hospital outpatient appointments. Hospital appointments are often booked weeks or months in advance, yet we found the same pattern there. So we don't think the pattern is driven by weekend recoveries.

Another line of evidence is that the weekday pattern does not show a spike on Monday followed by a flatline, as might be expected if weekend recoveries drive the effect. Instead, the decline is steady and gradual from Monday to Friday. Summary data can be seen here:

http://infogr.am/Weekday-...