Need to average a summed field

[LisaRR]

I need to calculate the average of a summary field. I need to calculate the average # of days a patient is on a ventilator for each unit.

The report is grouped by Unit and Patient Account #.
# of ventilator days per patient is a summary field:

Patient Name On Vent Y/N
Patient A - Y
Patient A - Y
Patient A - Y
Summary - Count of vent days for patient A = 3

Patient B - Y
Patient B - Y
Summary - Count of vent days for patient B = 2

When I try to create a formula to average the count of vent days per patient, I get an error message that says "This Field Cannot Be Summarized"

I have tried counting the vent days per patient as both a summary and a running total but am still not able to average the results. Thanks to anyone who can give me some direction on this.

 

[lbass]

How did you calculate the count of vent days per patient? What is the content of the formula you used? You didn't show a date field or any instances where the value <> "Y".

-LB

 

[LisaRR]

In the Select Expert, I am qualifying "On A Vent YN" = Y. There will not be any data where the value <> "Y".

I am counting the field "On a Vent YN" to get the count of vent days per patient. In my example above, Patient A has 3 entries in the field representing 3 separate days, so the count of vent days = 3.

There is a date range selection on a field called "Calendar Date". This is the actual date that the patient is on a vent.

 

[lbass]

Create a formula like this in the field explorer->formulas->new:

count({table.on_a_vent_YN})/distinctcount({table.patientID})

Place this in the report footer (or report header).

-LB

 

[LisaRR]

Thanks - I was able to get that formula to work with a little tweaking to accommodate the groupings in the report. I think I was making it more complicated than it needed to be. I appreciate your fast assistance! Lisa