Why use percent and average for improvement projects?

It seems that every healthcare quality improvement presentation I hear nowadays uses averages and percents as the mechanism for demonstrating an improvement was made. I have some problems with this:

1. There seems to be a confusion between performance management and measurement for improvement. Yes, the organisation may need to report on the % of x - done mostly so someone in charge can make a comparison. However, this is no reason to replicate this measurement in the project. For instance, if you're working on length of stay (LOS) then you may find mode (most frequently occurring number) is more helpful in demonstrating a change consequent to your improvement activities and it has the benefit of indicating the experience for most patients.
2. When a nurse pointed out to be that they do not have .32 of a bed then I took notice. Of course she was right. So some stats that showed an average of 12.32 beds were to be shifted each month (a specific project) I could see this was nonsense. Statistically it could be argued this made sense, though as a mechanism for engaging staff, working in whole numbers, whole beds, whole patients, tends to make more sense.
3. So ward A delivers a 4.18 average length of stay. Management now want all wards to achieve this (let's assume most are higher than this). So the processes and procedures underway in A is replicated to others (or attempted). The difficulty is their case mix may be different, their problem may be one where only their long stayer need to be addressed (they have the same mode but ave stats skewed the total figures) etc. In aiming for an average do they figure out the mathematics of LOS - x number can be 4 days, y number can be 5 days etc? For this is what the average leads them to - to game.
4. An average, is, by definition, an abstract concept that assumes half the values will be above the line and half below the line. Do you really want to have half your experiences, interventions etc be more than the agreed number?
5. One more measurement challenge. What happened to the 100% (or 0%) target? The common version is 98% of y or 95% of z. My logic suggests we are designing systems for a percentage failure. This is a tough call in healthcare. Which 2% of patients will you choose not to have optimal care for their diabetes?

3 tips for measuring the spread of good practice

1. The most basic spread / adoption chart is one which measures the number of people adopting a good practice over time; that is, people on the vertical axis, time on the horizontal axis. If you're not prepared to do this check then do comment in this blog and let me know how else you keep track of progress.

2. Calculate your total population who you would like to adopt the good practice. Work out how long this might take. Then pick yourself up off the floor.... Now work out that from this total amount, what might be a realistic target for the timescale and resources that you have for the project.

Why does this matter? Look at the picture above. Without having thought about the total intent of the spread programme, it is quite possible for a shorter period to show results like those under the red lines. When the project then ends, and measurement continues, then the results look like they take a nosedive. This is when measurement usually stops.

One of the reasons for working out the total intent before starting the spread programme, is to provide for some creative thinking. You may just go about the process in a different way if you knew that eventually there were going to be 25,000 staff using the new method, across 14 locations and it was likely to take seven years.

3. Einstein was on to something with his work on time and space. We've no need to get that deep into the mathematics when working on spreading good practice. However, the issue of space is an important one; or maybe you think of it easier as geography. I've seen some teams use excellent maps and nowadays there are interactive electronic maps on which data can be tagged. Think and get creative. Learn about how and why different practices spread in different ways, not just because of the peopel involved but also because of the space and geography.

Three basics to remember for spread measurement.

People.

Time.

Space.

(c) 2008, Sarah Fraser