| Literature DB >> 23935229 |
Abstract
Randomized controlled trials (RCTs) are increasingly playing a central role in shaping policy for development. By comparison, social experimentation has not driven the great transformation of welfare within the developed world. This introduces a range of issues for those interested in the nature of research evidence for making policy. In this article we will seek a greater understanding of why the RCT is increasingly seen as the 'gold standard' for policy experiments in low- and middle-income countries (LMICs), but not in the more advanced liberal democracies, and we will explore the implications of this. One objection to the use of RCTs, however can be cost, but implementing policies and programmes without good evidence or a good understanding of their effectiveness is unlikely to be a good use of resources either. Other issues arise. Trials are often complex to run and ethical concerns often arise in social 'experiments' with human subjects. However, rolling out untested policies may also be morally objectionable. This article sheds new light on the relationship between evidence and evaluation in public policy in both the global north and developing south. It also tackles emerging issues concerning the 'use' and 'misuse' of evidence and evaluation within public policy.Entities:
Keywords: Evidence-based policy; Impact evaluation; International comparisons; Knowledge utilization; Social research
Year: 2013 PMID: 23935229 PMCID: PMC3736249 DOI: 10.1111/spol.12024
Source DB: PubMed Journal: Soc Policy Adm ISSN: 0144-5596
Figure 1Randomized controlled trials (RCTs)
Source: adapted from Sibbald and Roland 1998: 201.
Figure 2Hierarchies of research evidence
Source: adapted from Davies et al. 2000: 48.
Figure 3Malawi RCT design
Source: Baird et al. 2009a: 7.
Figure 4Different prospects for the world's poorest
Source: adapted from Banerjee and Duflo 2011: 12–13.
Impact of CTT programmes on children's attendance at health centres
| Country | Country income categories | Programme | Baseline (%) | Impactα | Significanceβ | Evaluation designγ |
|---|---|---|---|---|---|---|
| Chile | Middle | 17.6 | 2.4(2.7) | RDD | ||
| Colombia | Middle | N/A | 33.2(11.5) | *** | DID | |
| Ecuador | Middle | N/A | 2.7(3.8) | RCT | ||
| Honduras | Middle | 44.0 | 20.2(4.7) | *** | RCT | |
| Jamaica | Middle | Program of Advancement through Health and Education | 0.2 | 0.3(0.08) | *** | RDD |
| Mexico | Middle | 0.2 | 0.03(0.02) | RCT | ||
| Nicaragua | Low | 70.5 | 6.3(2.0) | *** | RCT | |
| Nicaragua | Low | 55.4 | 13.1(7.5) | * | RCT | |
Source: Fiszbein et al. (2009: 19–20).
Notes: N/A = not applicable or comparable with control baseline; α = the column for ‘impact’ reports the coefficient and standard error (in parentheses); the unit is percentage points except Jamaica where the unit is the number of visits to the health centre in the past six months, and Mexico, where the unit is the number of visits to the health centre in the last six months; β = significance levels: * < 0.05, ** < 0.01, *** < 0.001; γ = RCT defined in figure 2; DID = difference-in-differences examines treatment effect by comparing the treatment group both before and after treatment, and to a control group; RDD = regression discontinuity design elicits intervention causal effects by exploiting a given exogenous threshold determining assignment to treatment. By comparing observations lying closely on either side of the threshold, it is possible to estimate treatment effect in situations where randomization was not feasible.
Impact of CTT programmes on children's attendance at school
| Country | Country income categories | Programme | Baseline (%) | Impactα | Significanceβ | Evaluation designγ |
|---|---|---|---|---|---|---|
| Chile | Middle | 60.7 | 7.5(3.0) | *** | RDD | |
| Colombia | Middle | 63.2 | 5.6(1.8) | *** | DID | |
| Ecuador | Middle | 75.2 | 10.3(4.8) | ** | RCT | |
| Honduras | Middle | 66.4 | 3.3(0.3) | *** | RCT | |
| Jamaica | Middle | Program of Advancement through Health and Education | 18.0 | 0.5(0.2) | ** | RDD |
| Mexico | Middle | 45.0 | 8.7(0.4) | *** | RCT | |
| Nicaragua | Low | 90.5 | 6.6(0.9) | *** | RCT | |
| Nicaragua | Low | 72.0 | 12.8(4.3) | *** | RCT | |
| Bangladesh | Low | Female Secondary School Assistance Programme | 44.1 | 12.0(5.1) | ** | FE |
| Cambodia | Low | Japan Fund For Poverty Reduction | 65.0 | 31.3(2.3) | *** | DID |
| Cambodia | Low | Cambodia Education Sector Support Project | 65.0 | 21.4(4.0) | *** | DID |
| Pakistan | Middle | Punjab Education Sector Reform | 29.0 | 11.1(3.8) | *** | DID |
| Turkey | Middle | Social Risk Mitigation Project | 87.9 | −3.0 | * | RDD |
Source: Fiszbein et al. 2009: 17–18.
Notes: α = the column for ‘impact’ reports the coefficient and standard error (in parentheses); the unit is percentage points except Jamaica where the unit is days; β = significance levels: * < 0.05, ** < 0.01, *** < 0.001; γ = RCT defined in figure 2; DID = difference-in-differences examines treatment effect by comparing the treatment group both before and after treatment, and to a control group; FE = a fixed effects statistical model represents the observed quantities in terms of explanatory variables that are treated as if the quantities were non-random, often used in the analysis of panel data; RDD = regression discontinuity design elicits intervention causal effects by exploiting a given exogenous threshold determining assignment to treatment. By comparing observations lying closely on either side of the threshold, it is possible to estimate treatment effect in situations where randomization was not feasible.
Impact of CTT programmes on food consumption
| Brazil | Colombia | Ecuador | Honduras | Nicaragua | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 2002 | 2002 | 2006 | 2005 | 2000 | 2002 | 2000 | 2001 | 2002 | ||
| Daily per capita food consumption | Control | 0.45 | 0.6 | 0.65 | 0.73 | 0.53 | 0.47 | 0.44 | 0.35 | 0.35 |
| Impact (%) | 12** | N/A | 6** | N/S | N/A | N/S | 38** | 31** | ||
| Food budget shares | Control (%) | 60 | 74 | 56 | 54 | 71 | 72 | 73 | 69 | 68 |
| Impact (% points) | 0.02** | N/A | 0.04** | 0.04** | N/A | N/S | 0.04** | 0.04** | ||
Source: Fiszbein et al. 2009: 113.
Notes: significance levels: * < 0.05, ** < 0.01, *** < 0.001; N/A = not applicable or comparable with control baseline; N/S = no significant or discernable impact.
Poverty measures for number of people (in millions) below $1.25 a day in 2005 purchasing power parities
| Country | Headcount | Poverty gapα | Squared poverty gapβ | |||
|---|---|---|---|---|---|---|
| Pre-transfer | Post-transfer | Pre-transfer | Post-transfer | Pre-transfer | Post-transfer | |
| Brazil | 0.2421 | 0.2369 | 0.0980 | 0.0901 | 0.0553 | 0.0471 |
| Ecuador | 0.2439 | 0.2242 | 0.0703 | 0.0607 | 0.0289 | 0.0235 |
| Jamaica | 0.2439 | 0.2329 | 0.0659 | 0.0602 | 0.0258 | 0.0224 |
| Mexico | 0.2406 | 0.2222 | 0.0847 | 0.0683 | 0.0422 | 0.0298 |
Source: Fiszbein et al. 2009: 110.
Notes: α = depth of poverty: this provides information regarding how far off households are from the poverty line; β = poverty severity: this takes into account not only the distance separating the poor from the poverty line (the poverty gap), but also the inequality among the poor. Thus, a higher weight is placed on those households who are further away from the poverty line.
Figure 5Estimates of chronic global povertyα
Source: Chen and Ravallion 2012: 5.
Note: α = number of people living below $1.25 a day in 2005 purchasing power parities.