Appendix C


Coder design effect (Groves, et al., 2009)


The coder design effect (deffc) applies much of the same logic as the interviewer design effect (see Interviewer Recruitment, Selection, and Training chapter).

  • In the formula for coder design effect below, ρc is the intraclass coefficient for coders, m is the average number of cases coded per coder, and r is the reliability of a particular (item) code.

deffc= 1 + ρc (m-1)(1-r)

  • The intraclass coefficient for coders is a measure of the ratio of coder variance to the total variance and is defined as:

ρc =data processing and statistical adjustment appendix b equation 02