Later this week we will send you the first validation of your data from the (SPOT)light study. We are calling this the “Heads’n’Tails” matching. The (SPOT)light visit is the head, and the tail is the admission to the Critical Care Unit participating in the Case Mix Programme (CMP). For every (SPOT)light patient who has gone to a critical care bed, we need to extract their critical care episode from the CMP, and for every critical care admission from the ward we need to identify their (SPOT)light visit.

It is only through this matching that we can time admission to critical care.

You will understand how crucial it is that we do not miss any patients both for the study as a whole, and for your own individual site report of 90 day survival. You will also agree, we hope, that we cannot assume that the missing cases do not matter. For example, if research documentation was missed because of time pressures when admitting the sickest patients then your report would then include only the less sick but more delayed cases. This would be an inaccurate and unfair description of your case load.

We are aiming to link 100% of cases, and if we fall significantly short of this then to avoid the risk of bias we cannot use your data.

However this is a pragmatic observational study which depends on the energy of busy clinical teams. Some missing data is inevitable which is why we are writing to explain the options that will be available. If there is a problem, then we can then work to use as much data as possible.

The options include …

• backfilling missing cases by pulling the notes of these patients. If required we would ask you to complete this process within one (1) month of the Heads’n’Tails validation report. If there is more work than can be reasonably done within this time frame, then you might consider
• switching to retrospective data collection (if you are currently collecting prospectively) to free up time for backfilling the existing data, or you might consider
• stopping data collection now (if you are already following the retrospective strategy) and focussing on backfilling your existing data. We would much prefer for all sites to complete one year’s data collection, but because we do want to discard any submitted data then an abbreviated but complete dataset is preferable to a longer incomplete one.

We are sending this notice now because this Wednesday (August 3) is changeover day for the junior medical staff. Please therefore consider reminding them of the inclusion criteria for the study, and highlighting that even when time pressure does not permit a Case Report Form to be completed simply documenting the fact of the visit (with the date and time) in the notes is enormously helpful as many of the vitals and laboratory measurements can be abstracted at a later date.

Yours sincerely

Steve (on behalf of the (SPOT)light team)