I have removed midpoints from a 5-point Likert scale instrument on my supervisor's advice. When I did some reliability analyses - SPSS showed that almost half of my cases were excluded. So we substituted the means for the missing cases. Is this right?
The midpoint was removed because it is assigned to answers such as: I don't know, neither agree/disagree. This can inflate the means. This is a conceptual argument that was made to me.