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// program : calcss-01.do
// task    : calculate sample size for 3x3 or 4x4 crossover design
// outcome : Sample size
// author  : Julie Wych
// date    : June 18
// version : 1.0
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// #1: set local macros
  local withsd = //set within-person SD here
  local est_effect = //set estimated trt effect here
  local power_req =  0.8 //set desired power to estimate trt effect eg. 0.8 or 0.9
  local min_subs =    //set minimum number of subjects required 

  mata : mata clear

// #2: 3x3 cross-over design
ssizeabc, sigma_e(`withsd') effect(`est_effect') req_power(`power_req') req_subs(`min_subs')

// #3: 4x4 cross-over design
ssizeabcd, sigma_e(`withsd') effect(`est_effect') req_power(`power_req') req_subs(`min_subs')