I'm trying to help out a not-for-profit organization and made an error that I'm trying to fix. They've been doing a non scientific survey of their Board of Directors for a number of years regarding board engagement. They asked me to help them convert the survey format from an unfriendly Excel file to something web based, handle the results and do some analysis for them.
In past years, they've used what I'm going to call a weighted scale (Very good = 5, Good = 3, Fair = 2, Poor = -1). This year, we mistakenly included an extra level by allowing a 5, 4, 3, 2, or 1 response. (That is, the previous questionnaires had 4 options, but this one has 5.)
I'm trying to figure out how to conform the scales to be roughly equivalent. I had been thinking that I could let 5 = 5, 4 = 3, 3 = 2.5, 2 = 2 and 1 = -1. However, I realize that this doesn't work and will skew everything lower.
Can anyone recommend a good way to handle this?