Huerta 2006 (PROGRESA).

Study characteristics
Methods	Study design: PCS How were missing data handled? missing data excluded Randomisation ratio: N/A Recruitment method: NR Sample size justification and outcome used: a subsample was chosen because a smaller number of children was adequate to assess the expected 2‐year impact on growth (0.8 cm) and anaemia (10 pp reduction). Sample size was calculated according to the original 2‐year intervention design for 1‐tailed tests, assuming a 0.05 significance level and a power of 90%. It was first estimated as a simple random sample, which was further multiplied by a design effect of 1.4 to take into account the complex sample design. Sampling method: nutritional impact substudy was conducted in a random selection of 205/320 communities scheduled to enrol in the programme at the end of 1998 and 142 communities randomly selected from the 186 communities that enrolled 1 year later, in late 1999. The communities for the larger PROGRESA evaluation were randomly selected; more details in Gertler 2000). Study aim or objective: to document the short‐term nutritional impact of a large‐scale, incentive‐based development programme in Mexico (Progresa) (Rivera 2004). To assess whether PROGRESA reduced the major childhood diseases that affect children aged < 5 years: diarrhoea and respiratory infections (Huerta 2006). Study period: August–September 1998 to November–December 2000 (data included a period when both groups were receiving the intervention) Unit of allocation or exposure: HHs
Participants	Baseline characteristics Intervention or exposure: NR Control: NR Overall: NR Inclusion criteria: poor households in rural areas where there is schooling and health infrastructure. Rivera 2004: infants aged 12 months. Huerta 2006: children aged 0–59 months. Gertler 2004: children aged < 3 years at baseline. Exclusion criteria: NR Pretreatment: True baseline data NR. Actual baseline data indicated no baseline differences between children aged ≤ 12 months, between the groups in terms of gender, age and anthropometric status (Rivera 2004). Socioeconomic and morbidity data N/A at baseline. Attrition per relevant group: From baseline to first follow‐up (1999): intervention: 172 children LTFU; control: 132 children LTFU. Description of subgroups measured and reported: Children aged 6 months at baseline or aged 12 months at baseline Total number completed and analysed per relevant group: total: 595 children (however, these are children surveyed in 2000, when control HHs had already been receiving the intervention for 1 year). Intervention: 336 children (2 years of exposure); control: 259 children (1 year of exposure) Total number enrolled per relevant group: 795 children. Exposed group (received intervention): 461 children (aged 12 months) from 175 communities; unexposed group (also termed crossover intervention group): 334 children (aged 12 months) from 107 communities Total number randomised per relevant group: N/A
Interventions	Intervention characteristics Intervention or exposure Food access intervention category: increase buying power Intervention type: CCT Description: families received 2 types of cash transfers every 2 months: a universal cash amount for all families and a specific cash transfer associated with school attendance of their school‐aged children enrolled in third‐grade primary school to third‐grade secondary school. Transfer associated with school attendance varied according to number of children attending school and their grade. PROGRESA provided micronutrient fortified foods for women and children and health services and cash transfers for family. Food supplements were targeted to the groups of individuals that were more likely to benefit from the product. Families received the universal cash transfer as long as they complied with specific healthcare appointments in health centres for all family members, including immunisations, well baby care and growth monitoring of children, antenatal and postnatal care and education for women, check‐up visits for other family members, and a mandatory session on nutrition and health education. Monthly transfers averaged about USD 25 per family. Typically, cash transfers added about 20–30% to HH income. Duration of intervention period: about 2 years: May 1998 to November 1999/March 2000 (?) Frequency: every 2 months Number of study contacts: 3: August–September 1998 (baseline); September–December 1999 and November–December 2000 Providers: federal government of Mexico Delivery: lump sum payment once completed forms were submitted by HHs to verify school attendance. Actual transfers to each HH depended on age and sex of children in HH and their compliance with the programme. About 1% of HHs were denied the cash transfers for non‐compliance during the evaluation period. Co‐interventions: none. 1 requirement of the PROGRESA programme was that HHs benefiting from PROGRESA were supposed to stop receiving benefits from other pre‐existing programmes. Resource requirements: access to health and educational facilities Economic indicators: national budget (1997): MXN 465.8 million (6357 localities; 301,262 families; 344,457 scholarships). Monthly transfers averaged about USD 25 per family. Typically, cash transfers added about 20–30% to HH income. Control: no intervention Co‐interventions: none. 1 requirement of the PROGRESA programme was that HHs benefiting from PROGRESA were supposed to stop receiving benefits from other pre‐existing programmes.
Outcomes	Anthropometry: LAZ or HAZ, WAZ, WLZ Biochemical: Hb Morbidity: anaemia, diarrhoeal disease, respiratory disease
Identification	Sponsorship source: CONACYT and the ESRC Research Centre for Analysis of Social Exclusion (CASE) at the London School of Economics; Mexican Ministry of Health. Country: Mexico Setting: poor rural HHs Authors' names: Juan A Rivera; Maria C Huerta Email: jrivera@correo.insp.mx; m.c.huerta@lse.ac.uk Declarations of interest: Mexican Ministry of Health commissioned the evaluation of the nutrition component of the Education, Health and Nutrition Program (Progresa) to a group of investigators of the Instituto Nacional de Salud Publica as independent evaluators. Ministry and its personnel did not participate in design, data collection or analysis. They did not participate in the preparation of manuscript or its authorisation for publication (Rivera 2004). No (Huerta 2006). Study or programme name and acronym: PROGRESA/Oportunidades Type of record: journal articles
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (Selection bias)	High risk	Nested cohort study design within a cRCT; therefore; no randomisation done.
Allocation concealment (Selection bias)	High risk	Nested cohort study design within a cRCT; therefore, no allocation concealment done.
Baseline characteristics similar (Selection bias)	Low risk	Data at baseline N/A, but some analyses showed that, although sample was balanced at community level, it was not at HH or individual level. However, authors accounted for potential confounders in their analyses. Quote: "In order to isolate the intervention effect from the possible influence of other background variables, we included a set of explanatory variables at the individual, household and community level."
Baseline outcome measurements similar (Selection bias)	Unclear risk	Data at baseline N/A.
Blinding of participants and personnel (Performance bias)	Low risk	No blinding; however, unlikely that the performance of participants and personnel were influenced by lack of blinding.
Blinding of outcome assessment (Detection bias)	High risk	Blinding not done. Health outcomes based on self‐report and could have been influenced by knowledge of treatment allocation. Authors reported evidence from preliminary analysis on biased reporting of these outcomes.
Protection against contamination (Performance bias)	High risk	There was contamination for some components of the intervention. Quote: "For ethical reasons, health centres provided supplements to malnourished children irrespective of whether they belonged to a control or a treatment community. Therefore, children in both types of localities could receive this in‐kind benefit" (Huerta 2006).
Incomplete outcome data (Attrition bias)	High risk	Very high levels of attrition/missing data after 1 year of the intervention: intervention: 172/461 (37%) children; control: 132/334 children (39%).
Selective outcome reporting (Reporting bias)	Unclear risk	No protocol available.
Other bias	High risk	Misclassification bias: low risk. Recipients registered as beneficiaries of programme. Measurement bias: high risk. Quote: "One of the limitations of these data is that information on health outcomes may suffer from reporting errors. In preliminary analyses, we found some evidence of reporting errors, specifically for respiratory infections." Incorrect analysis: low risk. Authors adjusted for clustering (this was a nested cohort of a cRCT)