Re: Normalizing scores

Posted by Art Kendall on Apr 28, 2013; 12:46pm
URL: http://spssx-discussion.165.s1.nabble.com/do-repeat-tp5719707p5719792.html

do you have the same respondents in both waves?  Can you tie responses to individuals?

What did they agree with?

did you have a series of items with the same response scale to create a summative score, or do you have a single item?

You could do a regression as Gerry suggested. 
On later waves you could as for both measures of performance.  You would then have
t1 vs t3 for satisfaction and
t2 vs t3 for agreement

However, I do not think you can conclude at this time that performance dropped.   You can conclude that the way that you measured performance changed.

Who changed the response format?  Were the stems identical, similar?
On 4/27/2013 8:24 PM, MR [via SPSSX Discussion] wrote:

Team,

I have one problem on my hand and am running out of options on which statistics to use in SPSS. First, I know that the what I want to do is not advisable but trust me, I have fought my battle on this. This is what I want to achieve:

Issue: We did wave 1 survey using 5-point satisfaction scale. The second wave was conducted using 5-point agreement scale. Expectedly, top-box scores from agreement scale when compared to top-box score of satisfaction scale was low by 10% points. For e.g., agreement scale top box in wave 2 came out as 50% while wave 1 it was 60%.

Goal: I have compared the historical data and conclude that score difference is purely due to scale change. However, i want to normalize the wave 2 score so that I can compare with wave 1. I know this is not advisable but I have to do this. I googled but could not find any statistics that helps to normalize the scores - indeed I don't know where to begin. I need a scientific method to normalize the scores so that they are comparable. I don't want to conclude that performance dropped by 10% just because scale changed.

Your wisdom and help is very much required.

Thanks,
Mike

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