Table 1.

Parameters needed to compute (r_opt;N_opt).

Parameter	Description
Pattern	Assumed pattern of the response Y (CMD or LDD)
σ 2	Diagonal element of the DEX covariance structure matrix of the response Y
ρ	Correlation between the first and the last measurements of the response Y
θ	Damping parameter of the DEX covariance structure matrix of the response Y
ρ e	Intraclass correlation of the exposure E
p e0	Prevalence of the exposure E at the first measurement (at time 0)
per	Prevalence of the exposure E at the last measurement (at the end of the follow-up)
π M	Proportion of subjects lost by the end of follow-up
κ	Ratio between the cost of the first measurement and each of the subsequent ones
c 1	Cost of the first measurement (including recruitment) for one participant
Budget a	Total budget for the study, including recruitment and follow-up
Power b	Target power of the study
α b	Significance level
${\tilde{\beta }}^b$ b	Effect size under the alternative hypothesis

^aIf interested in maximizing the power of the study without exceeding a fixed budget.

^bIf interested in minimizing the total cost of the study while achieving a certain target power.