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

• In the following formula for coder design effect, \(\rho_{c}\) 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: \(\text{deff}_{c}=1+\rho_{c}(m-1)(1-r)\).
• The intraclass coefficient for coders is a measure of the ratio of coder variance to the total variance and is defined as \(\rho_{c}=\frac{\text{between-coder variance}}{\text{between-coder variance}+\text{within-coder variance}}\).

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