This is probably something that I covered in previous posts, but I will say it a second time. When you work with a survey tool that will be scored, the likert scale converts into interval. Scoring of the survey requires either a mean or sum to be calculated from the items in your questionnaire. So another words, the likert scale is supposed to associate numbers with a qualitative meanings. Suppose a survey participant answered : 1=Strongly Disagree; 3=Nuetral, and 4= Mildly Agree. The sum score would be 1+3+4=8 (If those were the only items available). And the average score is 8/3=2.7. Our scores are no longer on the likert scale because we are using it for calculations. Now we do we care? Because there are certain tests we can not perform on interval data. For example, a Chi-Square is not a statistic for an interval variable. Categorical or count data is the format requirement for using a Chi Square test. Please keep it in mind when you stare at a likert scale survey tool with the score as the dependent variable.
-Moore to Follow Amy