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Table 6 Power calculations for some selected variables

From: Design of a multi-site multi-state clinical trial of home monitoring of chronic disease in the community in Australia

Outcome measure all on the monthly scale Effective sample size? Assumed normal distribution Shift amount (K) SPower
PBS Total cost 30 Log(PBS Total cost+1) 1 1.00
MBS out of hospital costs 30 Log(MBS out of hospital costs+1) 1 1.00
MBS in hospital costs 30 Log(MBS in hospital costs+1) 1 0.84
Number of hospital admissions 30 Square root the number of hospital admissions 0.5 0.99
Number of GP visits during working hours 30 Square root of number of GP visits during working hours 0.5 0.89
Number of GP visits outside of working hours 30 Square root of number of GP visits outside of working hours 0.1 0.50
Total number of GP visits 30 Square root of total number of GP visits 1 0.97
Total number of either Specialist, Psychiatric, Allied Health visits and Procedures 30 Square root of total number of either Specialist, Psychiatric, Allied Health visits and Procedures 1 0.77
Total number of Laboratory tests 30 Square root of total number of Laboratory tests 1 0.97
Number of Laboratory 30 Square root of number of Laboratory 1 0.96
Tests   Tests   
  1. The actual results may be much more complicated than this because the differences between the outcome variables may be auto correlated. This is particularly true if the test patient and the matched control patient outcome measures have different time series trends. Testing of whether the matched differences are auto correlated will be carried out when data becomes available but is not expected to be a significant problem.