a$.$

External OD consultants have more training in psychology than internal OD practitioners.

b$.$

External OD consultants have less experience than internal OD consultants.

c$.$

External OD consultant spend less time in OD than do internal OD practitioners.

d$.$

External OD consultants do not generally differ in experience, education, or training from internal OD practitioners.

e$.$

External OD consultants are younger than internal OD consultants.