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Table 9 P4P Average causal mediation effect (ACME) and direct effects, sensitivity analysis using Imai et al. (2010) approach

From: Understanding causal pathways within health systems policy evaluation through mediation analysis: an application to payment for performance (P4P) in Tanzania

  Mediation analysis Sensitivity results
  Mean [95% Conf. Interval]  
Mediators for delivery in health facility
Oxytocin stock-out
ACME 0.017 0.006 0.028   
Direct effect 0.059 0.021 0.095 Correlation at which ACME = 0 −0.0439
Total effect 0.077 0.041 0.109   
% of tot eff mediated 0.226 0.159 0.424   
Health worker kindness
ACME 0.039 0.031 0.048   
Direct effect 0.042 0.007 0.075 Correlation at which ACME = 0 0.2085
Total effect 0.081 0.045 0.116   
% of tot eff mediated 0.482 0.337 0.864   
Percentage of women who paid for delivery in HF
ACME 0.041 0.032 0.051   
Direct effect 0.040 0.004 0.072 Correlation at which ACME = 0 −0.2326
Total effect 0.081 0.045 0.113   
% of tot eff mediated 0.511 0.364 0.911   
Mediators for delivery in public HF
Oxytocin stock-out
ACME 0.019 0.008 0.031   
Direct effect 0.037 0.000 0.077 Correlation at which ACME = 0 −0.0437
Total effect 0.057 0.021 0.096   
% of tot eff mediated 0.342 0.202 0.933   
Health worker kindness
ACME 0.033 0.026 0.042   
Direct effect 0.031 −0.008 0.068 Correlation at which ACME = 0 0.161
Total effect 0.065 0.024 0.102   
% of tot eff mediated 0.516 0.325 1.374   
Percentage of women who paid for delivery in HF
ACME 0.051 0.039 0.062   
Direct effect 0.014 −0.025 0.050 Correlation at which ACME = 0 −0.259
Total effect 0.064 0.025 0.100   
% of tot eff mediated 0.791 0.506 2.051   
Mediators for IPT2 uptake
Health workers received supervision visit in last 90 days
ACME 0.016 0.002 0.030   
Direct effect 0.102 0.038 0.161 Correlation at which ACME = 0 −0.0343
Total effect 0.117 0.056 0.174   
% of tot eff mediated 0.133 0.089 0.280   
  1. ACME average causal mediation effect