the midpoint

Bob Green (
Wed, 5 May 1999 22:15:34 +1000

Recently I was having an e-mail discussion regarding the midpoint, as often
used in repertory grids. The midpoint can denote either a middle value or
that the construct is not applicable (NA). These are different issues,
though at times the midpoint is used as a catchall for both issues.

As I understand it options include:

a) forced choice/don't include a midpoint

b) the midpoint is labelled, as a bit like both etc or a bit like neither or NA

c) transform the scale into a unipolar scale, with 0 = NA etc

d) treat NA as a missing value, though I'm not sure of grid programs that
allow for this.

I would be interested to hear other suggestions or preferences,


Bob Green