Statisticians - Which ones of the below is the correct formula for Level 2 Knowledge Lift on a test that has 100% as the maximum score?
1. (posttest score - pretest score / (100-pretest score)
or
2. (posttest score - pretest score) / pretest score

helen,

Neither. All you have is another measure of knowledge...but not one that can be useful.

The person may know more or less...but you don't know whether the change comes from adding new knowledge, dropping some, or dropping some and replacing it with something new.

In fact, a person could have an identical percentage score on a reassessment yet....has not done well on an area where they did well previously and is doing well on an area where they had not done well before.

Of course, all this goes out the window if your testing allows you to track learning by specific items.

Not a statistician so please don't bet any money on my reply :-)

Jeff

Thank you for your reply. As you feel the formula does not provide measurable evaluation of the Level 2 Knowledge Lift - how does your company measure Level 2 Knowledge Lift? Or how do you measure Level 2 in general? Do you use pre/post test, control group, or baseline of previous students on those questions, etc? Thank you.

Actually, I have a consulting practice that develops and administers 360 surveys and assessments. Testing is not a focus area, gathering feedback about performance is....(more about 360 FAQ's from my blog at www.360fyi.com.)

Having said that, any pre/post assessments are set up to insure each behavior/practice/competency can be compared pre/post. Apples to apples, oranges to oranges....etc.

This may be exactly what you are already doing.

The larger (and in my opinion more important) metric is that off determining the degree to which the skills survived the trip back into the workplace (Level 3). That is where performance change matters and where it is so often neglected. I like to do post training support surveys to see just how the student feels the organization is supporting them with mentoring, coaching, new work that uses the new skills...etc.