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

Table 3 Effect of P4P on institutional delivery and on potential mediators

	Effect of P4P (% change)	Observations
Maternal care outcomes
Facility-based delivery	8.2*** (3.6; 12.8)	5747
Public facility delivery	6.5** (1.3; 11.7)	5747
Taken at least 2 doses of anti-malaria drug	10.3*** (4.4; 16.1)	4759
Potential mediators
Health workers received supervision visit in the last 90 days	18.0** (4.0; 32.0)	5100
Drug stock-out index-general (0–1 index)	−17.2***^BS (−28.6;−5.8)	5659
Drugs at delivery stock-out index (0–1 index)	−27.0***^BS (−43.4;−10.6)	5639
Oxytocin injection stock-out last 90 days	−36.2***^BS (−55.9;−16.4)	5618
Ergomentrin injection stock-out last 90 days	−26.1** (−48.2;−4.0)	5562
Medical supplies stock-out index (0–1 index)	−14.8***^BS (−24.8;−4.9)	5278
Service delivery disrupted due to broken equipment last 90 days	−14.9** (−29.3;−0.4)	5602
Health worker knowledge	18.8***^BS (10.4; 27.2)	5461
Kindness ranks for health workers at delivery	4.3* (−0.4; 9.0)	5747
Percentage of women who paid for delivery in a HF	−4.5* (−9.5; 0.6)	5750

BS Significant at 5% level with Bonferroni adjusted p value for multiple outcomes: Bonferroni adjusted p value for potential mediators within three major groups: Financing 0.0047, governance 0.0017, human resources 0.0414. Indicators within each category in Table 1 have been grouped into: governance (strengthened supervision, active governing committees, increased outreach activities), financing (availability of drugs, medical supplies and equipment, increase insurance enrolment, reduction in user charges), and human resources (health worker more motivated and knowledgeable, improved patient provider interactions, adherence to clinical protocol). 95% confidence intervals in parentheses. Percent sign (%) indicates percentage points change
*p < 0.10; **p < 0.05; ***p < 0.01

ISSN: 1748-5908