Table 1 Bradford Hill criteria for evaluating the quality of studies

Strength of association

▪ 1. Is there a statistically significant causal effect?

1

▪ 2. Is the significance level very strong, indicated by a p value of less than 0.01?

1

▪ 3. Does the coefficient show a strong association, with coefficients equal to 2.0 or greater considered strong in this context? For instance, DiD HR ≥ 2.0 would suggest a strong association

1

Consistency

▪ Has the study examined multiple outcome measures related to the mortality of children under the age of five? These outcome measures include neonatal, infant, and post-infant mortality rates, in addition to overall U5 mortality

1

▪ Are there any patterns or similarities in the findings when comparing any two of these outcome measures?

1

Specificity

▪ Were the interventions designed to specifically reduce mortality among children under the age of five?

1

Temporality

▪ Was the implementation of interventions carried out before the impact on U5 mortality was observed?

1

Biological gradient

▪ Was the endline survey conducted after giving the interventions a year or more to mature?

1

Plausibility

▪ Is the relationship between U5 mortality and HSS interventions supported by existing literature?

1

▪ Have other observable factors in the model been chosen based on existing literature?

1

Coherence

▪ Is the interpretation of the findings in line with existing literature?

1

Experiment

▪ Is the design of the study appropriate to establish a causal effect?

1

▪ Are the methods employed suitable for establishing causal effect?

1

Analogy

▪ Based on the literature, did the study formulate a hypothesis to test the relationship between HSS interventions and child survival?

1