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Table 3 Performance matrix

From: Measuring skin necrosis in a randomised controlled feasibility trial of heat preconditioning on wound healing after reconstructive breast surgery: study protocol and statistical analysis plan for the PREHEAT trial

Criteria

Outcome measure

Necrosis Y/N

Depth (SKIN)

Total necrosis area

Subjectivity of measurement

(κ for the first and second clinical assessment)*

   

Sample size required to demonstrate statistically significant difference between treatment and control arm (based on observed data)†

   

Proportion of patients with observed response**

   
  1. *For total necrosis area, we include κ where area is assumed to be 0 mm2 when no necrosis present is recorded. †For necrosis Y/N sample size will be determined for a two sample proportions test. For total area, sample size will be computed using non-parametric methods for non-normally distributed continuous data [22]. For necrosis depth sample size calculation for ordered categorical data will be performed using the observed proportions in each category [23]. **For total necrosis area, we will present the proportion of patients with an observed area response where area is assumed to be 0 mm2 where no necrosis present is recorded
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Pilot and Feasibility Studies

ISSN: 2055-5784