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75-646: Oportunidades championed the conditional cash transfer (CCT) model for programs instituted in other countries, such as a pilot program in New York City, the Opportunity NYC , and the Social Protection Network in Nicaragua . Other countries that have instituted similar conditional cash transfer programs include Brazil , Peru , Honduras , Jamaica , Chile , Malawi and Zambia . Progresa-Oportunidades

150-445: A mean cost of US$ 12 million per RCT. Nevertheless, the return on investment of RCTs may be high, in that the same study projected that the 28 RCTs produced a "net benefit to society at 10-years" of 46 times the cost of the trials program, based on evaluating a quality-adjusted life year as equal to the prevailing mean per capita gross domestic product . The conduct of an RCT takes several years until being published; thus, data

225-548: A lack of personal equipoise (e.g., a personal belief that an intervention is effective). Finally, Zelen's design , which has been used for some RCTs, randomizes subjects before they provide informed consent, which may be ethical for RCTs of screening and selected therapies, but is likely unethical "for most therapeutic trials." Although subjects almost always provide informed consent for their participation in an RCT, studies since 1982 have documented that RCT subjects may believe that they are certain to receive treatment that

300-407: A new direction. And officials often had more to gain politically from abandoning this program and starting a new one. As a centrally administered program, Oportunidades allows for low operational costs and a greater level of efficiency in the transmission of benefits directly to the participants in the program. The program has sometimes been criticized for this completely “top down” approach. However,

375-524: A prerequisite for publication. One way to classify RCTs is by study design . From most to least common in the healthcare literature, the major categories of RCT study designs are: An analysis of the 616 RCTs indexed in PubMed during December 2006 found that 78% were parallel-group trials, 16% were crossover, 2% were split-body, 2% were cluster, and 2% were factorial. RCTs can be classified as "explanatory" or "pragmatic." Explanatory RCTs test efficacy in

450-522: A procedure for a given study based on its advantages and disadvantages. This is a commonly used and intuitive procedure, similar to "repeated fair coin-tossing." Also known as "complete" or "unrestricted" randomization, it is robust against both selection and accidental biases. However, its main drawback is the possibility of imbalanced group sizes in small RCTs. It is therefore recommended only for RCTs with over 200 subjects. To balance group sizes in smaller RCTs, some form of "restricted" randomization

525-438: A relatively comprehensive listing of the documents and databases produced during all of the evaluation rounds. Communications between IFPRI and Progresa's leadership commenced in late 1997, with the final contract ($ 2.5 million USD) signed during the third quarter of 1998. The IFPRI-Progresa research team's overall objective was to "determine if Progresa was functioning in practice as it [was] intended to by design." The evaluation

600-540: A research setting with highly selected participants and under highly controlled conditions. In contrast, pragmatic RCTs (pRCTs) test effectiveness in everyday practice with relatively unselected participants and under flexible conditions; in this way, pragmatic RCTs can "inform decisions about practice." Another classification of RCTs categorizes them as "superiority trials", "noninferiority trials", and "equivalence trials", which differ in methodology and reporting. Most RCTs are superiority trials, in which one intervention

675-522: A standard for poverty reduction programs in the developing world." The evaluation remains one of the programs' most celebrated features, having "inspired many others in Latin America and other regions." CCTs worldwide have drawn from the Oportunidades' model, often through direct consultation with its designers and managers. Subsequent evaluations of Oportunidades and other CCT programs have corroborated

750-400: A universe of 1,850 to choose 191 control localities, using a distribution proportional to the size of the locality.” Attrition bias is a well-known issue in quantitative study designs which can create a situation "analytically similar" to selection bias in that "attrition lead[s] to selective [read: systematically different] samples." "The IFPRI evaluation did not follow up migrants as part of

825-534: A ‘developing’ country context to use randomized controlled trial (RCT) research design. In the perennial debates surrounding the RCT as a tool of social policy evaluation IFPRI-Progresa provided (and continues to provide) an important proof-of-concept, an example exalted by proponents and held aloft before critics. Original sample selection took place in mid-1997. All available information indicates that personnel at Secretaría de Desarrollo Social, Mexico undertook and directed

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900-617: Is a form of scientific experiment used to control factors not under direct experimental control. Examples of RCTs are clinical trials that compare the effects of drugs, surgical techniques, medical devices , diagnostic procedures , diets or other medical treatments. Participants who enroll in RCTs differ from one another in known and unknown ways that can influence study outcomes, and yet cannot be directly controlled. By randomly allocating participants among compared treatments, an RCT enables statistical control over these influences. Provided it

975-412: Is an important part of the scientific method . Reviewers examine the study results for potential problems with design that could lead to unreliable results (for example by creating a systematic bias ), evaluate the study in the context of related studies and other evidence, and evaluate whether the study can be reasonably considered to have proven its conclusions. To underscore the need for peer review and

1050-428: Is available, a placebo may be used in the control group so that participants are blinded to their treatment allocations. This blinding principle is ideally also extended as much as possible to other parties including researchers, technicians, data analysts, and evaluators. Effective blinding experimentally isolates the physiological effects of treatments from various psychological sources of bias . The randomness in

1125-476: Is best for them personally; that is, they do not understand the difference between research and treatment. Further research is necessary to determine the prevalence of and ways to address this " therapeutic misconception ". The RCT method variations may also create cultural effects that have not been well understood. For example, patients with terminal illness may join trials in the hope of being cured, even when treatments are unlikely to be successful. In 2004,

1200-578: Is choosing a randomization procedure to generate an unpredictable sequence of allocations; this may be a simple random assignment of patients to any of the groups at equal probabilities, may be "restricted", or may be "adaptive." A second and more practical issue is allocation concealment , which refers to the stringent precautions taken to ensure that the group assignment of patients are not revealed prior to definitively allocating them to their respective groups. Non-random "systematic" methods of group assignment, such as alternating subjects between one group and

1275-410: Is designed to be a centrally run program that relies on a horizontal integration of programs and services among the agencies and ministries in the executive branch. This required the establishment of a body with enough power to coordinate the participants in the program and monitor the budget. Instead of restructuring an old agency, it was decided to form a new agency with all of the appropriate powers and

1350-438: Is designed well, conducted properly, and enrolls enough participants, an RCT may achieve sufficient control over these confounding factors to deliver a useful comparison of the treatments studied. An RCT in clinical research typically compares a proposed new treatment against an existing standard of care ; these are then termed the 'experimental' and 'control' treatments, respectively. When no such generally accepted treatment

1425-474: Is hypothesized to be superior to another in a statistically significant way. Some RCTs are noninferiority trials "to determine whether a new treatment is no worse than a reference treatment." Other RCTs are equivalence trials in which the hypothesis is that two interventions are indistinguishable from each other. The advantages of proper randomization in RCTs include: There are two processes involved in randomizing patients to different interventions. First

1500-437: Is necessary to consider things other than design, such as heterogeneity, population, intervention or comparator. Two other lines of reasoning question RCTs' contribution to scientific knowledge beyond other types of studies: Like all statistical methods, RCTs are subject to both type I ("false positive") and type II ("false negative") statistical errors . Regarding Type I errors, a typical RCT will use 0.05 (i.e., 1 in 20) as

1575-431: Is not possible to implement a satisfactory sample-selection-correction model," the word 'attrition' appears only once. The rest of the report frames the use of both samples as a form of robustness testing. This framing turns attention away from attrition bias, instead highlighting the dual-sample testing as a strength of the analysis. Behrman and Todd (1999) discuss attrition more extensively. Here, contamination refers to

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1650-404: Is recommended that allocation concealment methods be included in an RCT's protocol , and that the allocation concealment methods should be reported in detail in a publication of an RCT's results; however, a 2005 study determined that most RCTs have unclear allocation concealment in their protocols, in their publications, or both. On the other hand, a 2008 study of 146 meta-analyses concluded that

1725-410: Is recommended. The major types of restricted randomization used in RCTs are: At least two types of "adaptive" randomization procedures have been used in RCTs, but much less frequently than simple or restricted randomization: "Allocation concealment" (defined as "the procedure for protecting the randomization process so that the treatment to be allocated is not known before the patient is entered into

1800-474: The International Committee of Medical Journal Editors (ICMJE) announced that all trials starting enrolment after July 1, 2005, must be registered prior to consideration for publication in one of the 12 member journals of the committee. However, trial registration may still occur late or not at all. Medical journals have been slow in adapting policies requiring mandatory clinical trial registration as

1875-414: The scientific literature . Not all RCTs are randomized controlled trials (and some of them could never be, as in cases where controls would be impractical or unethical to use). The term randomized controlled clinical trial is an alternative term used in clinical research; however, RCTs are also employed in other research areas, including many of the social sciences . The first reported clinical trial

1950-507: The 1880s, and in education . The earliest experiments comparing treatment and control groups were published by Robert Woodworth and Edward Thorndike in 1901, and by John E. Coover and Frank Angell in 1907. In the early 20th century, randomized experiments appeared in agriculture, due to Jerzy Neyman and Ronald A. Fisher . Fisher's experimental research and his writings popularized randomized experiments. The first published Randomized Controlled Trial in medicine appeared in

2025-499: The 1948 paper entitled " Streptomycin treatment of pulmonary tuberculosis ", which described a Medical Research Council investigation. One of the authors of that paper was Austin Bradford Hill , who is credited as having conceived the modern RCT. Trial design was further influenced by the large-scale ISIS trials on heart attack treatments that were conducted in the 1980s. By the late 20th century, RCTs were recognized as

2100-650: The Inter-American Development Bank (IDB) for the expansion of the program was negotiated during 2001, and disbursed beginning in 2002. In 2003, the Ley General de Desarollo Social (General Law of Social Development, LGDS) explicitly codified the requirement for independent evaluation for all federally run Mexican social programs and for this purpose established the Consejo Nacional de Evaluación (National Council on Evaluation, CONEVAL). The excitement for

2175-499: The Zedillo and Fox administrations was a crucial test of the long-term sustainability of Progresa-Oportunidades. President Fox’s administration achieved early public recognition for its commitment to anti-poverty strategies as well as its willingness to continue with earlier initiatives that had proved to be successful. Fox ultimately decided to continue with the program because its independent image meant that it had not become identified with

2250-543: The assessor or obtain an objective source of data for evaluation of outcomes." The types of statistical methods used in RCTs depend on the characteristics of the data and include: Regardless of the statistical methods used, important considerations in the analysis of RCT data include: The CONSORT 2010 Statement is "an evidence-based, minimum set of recommendations for reporting RCTs." The CONSORT 2010 checklist contains 25 items (many with sub-items) focusing on "individually randomised, two group, parallel trials" which are

2325-558: The assignment of participants to treatments reduces selection bias and allocation bias, balancing both known and unknown prognostic factors, in the assignment of treatments. Blinding reduces other forms of experimenter and subject biases . A well-blinded RCT is considered the gold standard for clinical trials. Blinded RCTs are commonly used to test the efficacy of medical interventions and may additionally provide information about adverse effects, such as drug reactions . A randomized controlled trial can provide compelling evidence that

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2400-429: The assignments in order to reduce the bias. Although the principle of clinical equipoise ("genuine uncertainty within the expert medical community... about the preferred treatment") common to clinical trials has been applied to RCTs, the ethics of RCTs have special considerations. For one, it has been argued that equipoise itself is insufficient to justify RCTs. For another, "collective equipoise" can conflict with

2475-603: The backing from the president. Although this provided for an easier and faster startup, it also meant that many of the related agency structures, which Progresa-Oportunidades would have to rely on for its sustainability, were incompatible with the new program. Officials in related structures such as the Ministry of Health and Education were not provided with the appropriate incentives to channel their work toward Progresa-Oportunidades. Many were individuals who had worked on earlier poverty programs and who now saw their resources shifting in

2550-532: The controversy surrounding the long rule of the Partido Revolucionario Institucional ( Institutional Revolutionary Party , PRI) and its social policies was already entrenched. Under ' New Federalism ,' president Ernesto Zedillo (1994–2000) was attempting to de-politicize social programs. One of the paramount objectives at the core of Progresa’s development, therefore, was to establish the program's apolitical status by sustaining it through

2625-439: The danger of overgeneralizing conclusions, two Boston-area medical researchers performed a randomized controlled trial in which they randomly assigned either a parachute or an empty backpack to 23 volunteers who jumped from either a biplane or a helicopter. The study was able to accurately report that parachutes fail to reduce injury compared to empty backpacks. The key context that limited the general applicability of this conclusion

2700-406: The definition of 'poor'/eligible households and increased the number of eligible households in the sample from 53% to 78% in the treatment group, and from 50% to 78% in the control group. As of November 1999, when the final round of ENCEL surveys was conducted, "819 of the 3023 densified households [27% of those added through densification, 3% of the overall sample] had been incorporated." Three of

2775-594: The end of the experiment period they would have been significantly unequal. As opposed to selection bias, which features prominently in the IFPRI-Progresa documentation, only two final reports mention attrition bias (which creates essentially the same problem as selection bias from an analytic point of view). Schultz (2000) carried out analyses of enrollment using a "panel sample" (households with data across all five survey rounds) and "pooled sample" (households with data in at least one survey round). While admitting that "it

2850-415: The estimated program effects." The targeting mechanisms Progresa employed were the subject of much discussion and varied across time. To summarize, Progresa targeted beneficiaries using a three-tiered mechanism: (1) the selection of marginal communities according to specially-developed marginality index, (2) the selection of poor households using a multidimensional poverty line, and (3) community validation of

2925-475: The evaluation surveys," and yet by November 2000, 17% of households and 29% of individuals from the original November 1997 sample were no longer in the survey. Moreover, "attrition differ[ed] significantly between treatment and control groups, even after controlling for household characteristics and the eligibility criteria." The presence of nonrandom attrition indicates that even if the samples were experimentally selected and statistically equivalent to begin with, by

3000-477: The final evaluation studies define 'eligible' households as only the group originally chosen for incorporation (pre-densification). Ten others employ the post-densification criteria, and finally two more experiment with both. IFPRI-Progresa catalyzed a number of changes in Mexican governance and global international development agendas. By the time Progresa began to form in the heads of Mexican social policy designers,

3075-601: The highest grade." However, a 2001 study published in Journal of the American Medical Association concluded that "discrepancies beyond chance do occur and differences in estimated magnitude of treatment effect are very common" between observational studies and RCTs. According to a 2014 (updated in 2024) Cochrane review, there is little evidence for significant effect differences between observational studies and randomized controlled trials. To evaluate differences it

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3150-491: The highest-quality evidence available are: Notable RCTs with unexpected results that contributed to changes in clinical practice include: Many papers discuss the disadvantages of RCTs. Among the most frequently cited drawbacks are: RCTs can be expensive; one study found 28 Phase III RCTs funded by the National Institute of Neurological Disorders and Stroke prior to 2000 with a total cost of US$ 335 million, for

3225-519: The hypothesis being tested. This suggestion contrasted starkly with the prevalent Enlightenment -era attitude that scientific observation can only be objectively valid when undertaken by a well-educated, informed scientist. The first study recorded to have a blinded researcher was published in 1907 by W. H. R. Rivers and H. N. Webber to investigate the effects of caffeine. Randomized experiments first appeared in psychology , where they were introduced by Charles Sanders Peirce and Joseph Jastrow in

3300-408: The lack of community participation in the identification of beneficiaries and the allocation of funding helps to limit the opportunities for corruption at the local level, which has traditionally been a problem with such government-funded programs. To effectively disseminate information about the program, Progresa-Oportunidades pursued a three-pronged strategy. First, an extensive amount of information

3375-501: The list of beneficiaries at a town meeting. The weighting of different household characteristics in the calculations of household (not community) eligibility was modified during mid-1999, between the IFPRI-Progresa surveys, a process dubbed densificación or densification (in response to "the tendency of the [targeting] method to classify as beneficiaries households with more children and to exclude smaller households or older households that have no young children,"). These adjustments shifted

3450-526: The most common type of RCT. For other RCT study designs, " CONSORT extensions " have been published, some examples are: Two studies published in The New England Journal of Medicine in 2000 found that observational studies and RCTs overall produced similar results. The authors of the 2000 findings questioned the belief that "observational studies should not be used for defining evidence-based medical care" and that RCTs' results are "evidence of

3525-534: The new program spread not only through Mexico, but through the IDB and World Bank, too. Both organizations extensively employed the example of IFPRI-Progresa to forward CCTs and EBP (via rigorous evaluation of social programs). The World Bank featured the program as a model in the 2004 Conference on Poverty in Shanghai, and in 2006 the former President James D. Wolfensohn commented "Progresa’s rigorous emphasis on evaluation has set

3600-511: The null hypothesis in the respective statistical test . The failure to reject the null hypothesis would imply that the treatment shows no statistically significant effect on the treated in a given test. But as the sample size increases, the same RCT may be able to demonstrate a significant effect of the treatment, even if this effect is small. An RCT may be blinded, (also called "masked") by "procedures that prevent study participants, caregivers, or outcome assessors from knowing which intervention

3675-546: The old ruling party (the PRI) or with former President Zedillo in the eyes of the public. In addition, Fox had received confirmation of the program’s benefits both from the program’s own impact evaluations and outside international financial institutions who held Oportunidades in high esteem and hoped to see it continue. Oportunidades has been hailed as a success by many in Mexico and globally. The first round of evaluations were carried out by

3750-525: The other, can cause "limitless contamination possibilities" and can cause a breach of allocation concealment. However empirical evidence that adequate randomization changes outcomes relative to inadequate randomization has been difficult to detect. The treatment allocation is the desired proportion of patients in each treatment arm. An ideal randomization procedure would achieve the following goals: However, no single randomization procedure meets those goals in every circumstance, so researchers must select

3825-569: The positive effects found in the results found by IFPRI-Progresa. Opportunity NYC Too Many Requests If you report this error to the Wikimedia System Administrators, please include the details below. Request from 172.68.168.150 via cp1114 cp1114, Varnish XID 471661094 Upstream caches: cp1114 int Error: 429, Too Many Requests at Fri, 29 Nov 2024 08:46:52 GMT Randomized controlled trial A randomized controlled trial (or randomized control trial ; RCT )

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3900-432: The possibility that "families or individuals from control localities or other localities [can] immigrate to treatment group localities in order to receive program services" (the term can refer to several other concepts). As with attrition bias, the decision to not track down sample out-migrants makes any quantification of this bias impossible. For later survey rounds, however, the outlook is worrisome: "The rapid expansion of

3975-572: The presidential switch in 2000. Vicente Fox Quesada , leader of the Partido Acción Nacional ( National Action Party , PAN), won the presidential elections on July 2, 2000 and took office on December 1. Surviving the presidential election cycle — a feat never before accomplished by a Mexican social program — Progresa endured through the first changeover of the national ruling party in 71 years. The IFPRI final reports were released primarily during this interval. Program supporters used

4050-852: The prestigious International Food Policy Research Institute (IFPRI), between 1997 and 2000. The #IFPRI-Progresa partnership played a large role in shaping Mexican social policy and in bringing the randomized controlled trial (RCT) to the forefront of policy evaluation worldwide. Since 2002, the Instituto Nacional de Salud Pública (National Public Health Institute, INSP) and the Centro de Investigaciones y Estudios Superiores en Antropología Social (Center for Research and Higher Studies in Social Anthropology, CIESAS) have been responsible for carrying out ongoing evaluations of both program operations and impact. The Oportunidades evaluation website contains

4125-444: The probability that the RCT will falsely find two equally effective treatments significantly different. Regarding Type II errors, despite the publication of a 1978 paper noting that the sample sizes of many "negative" RCTs were too small to make definitive conclusions about the negative results, by 2005-2006 a sizeable proportion of RCTs still had inaccurate or incompletely reported sample size calculations. Peer review of results

4200-449: The process before the arrival of most of the IFPRI research team. One of the most detailed accounts is as follows: "The design of the impact evaluation of Progresa in communities and households is quasi-experimental...To undertake this component of the evaluation, a random sample of communities with 'high' or 'very high' degrees of marginalization were selected which would be incorporated into

4275-406: The production of far more technical documents, reports, and later, published journal articles and books. The results of IFPRI's initial evaluations began to form into reports in late 1999 and early 2000; most final reports (18 in total) were submitted before the end of 2000, with the executive synthesis report published on September 1 that year. The thematic core of the IFPRI evaluations conformed to

4350-404: The program being used for political proselytizing. In 2000 and 2003, program officials were prohibited from signing up new beneficiaries within six months of national elections to prevent vote buying. In addition, budget provisions have been enacted that attempt to directly communicate with beneficiaries to educate them about rights and responsibilities regarding the program. The transition between

4425-404: The program during Phase II (November 1997) and which would serve as the [treatment] communities...Another sample of communities with similar characteristics was randomly designated from those that could have been the object of later selection, and that could function as controls...the size of the sample was estimated starting from a universe of 4,546 localities to choose 330 base localities, and from

4500-432: The program, even before households in the original control communities started receiving transfers, meant that control communities often literally were surrounded by other communities that were already receiving them. Under such circumstances, it is likely that households in the control communities may have expected to receive [Progresa] transfers before they actually started to receive them, which complicates interpretation of

4575-446: The results of RCTs with inadequate or unclear allocation concealment tended to be biased toward beneficial effects only if the RCTs' outcomes were subjective as opposed to objective . The number of treatment units (subjects or groups of subjects) assigned to control and treatment groups, affects an RCT's reliability. If the effect of the treatment is small, the number of treatment units in either group may be insufficient for rejecting

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4650-666: The results of the study. Adequate allocation concealment should defeat patients and investigators from discovering treatment allocation once a study is underway and after the study has concluded. Treatment related side-effects or adverse events may be specific enough to reveal allocation to investigators or patients thereby introducing bias or influencing any subjective parameters collected by investigators or requested from subjects. Some standard methods of ensuring allocation concealment include sequentially numbered, opaque, sealed envelopes (SNOSE); sequentially numbered containers; pharmacy controlled randomization; and central randomization. It

4725-439: The results of unblinded RCTs tended to be biased toward beneficial effects only if the RCTs' outcomes were subjective as opposed to objective; for example, in an RCT of treatments for multiple sclerosis , unblinded neurologists (but not the blinded neurologists) felt that the treatments were beneficial. In pragmatic RCTs, although the participants and providers are often unblinded, it is "still desirable and often possible to blind

4800-567: The standard method for "rational therapeutics" in medicine. As of 2004, more than 150,000 RCTs were in the Cochrane Library . To improve the reporting of RCTs in the medical literature, an international group of scientists and editors published Consolidated Standards of Reporting Trials (CONSORT) Statements in 1996, 2001 and 2010, and these have become widely accepted. Randomization is the process of assigning trial subjects to treatment or control groups using an element of chance to determine

4875-440: The study treatment causes an effect on human health. The terms "RCT" and "randomized trial" are sometimes used synonymously, but the latter term omits mention of controls and can therefore describe studies that compare multiple treatment groups with each other in the absence of a control group. Similarly, the initialism is sometimes expanded as "randomized clinical trial" or "randomized comparative trial", leading to ambiguity in

4950-442: The study") is important in RCTs. In practice, clinical investigators in RCTs often find it difficult to maintain impartiality. Stories abound of investigators holding up sealed envelopes to lights or ransacking offices to determine group assignments in order to dictate the assignment of their next patient. Such practices introduce selection bias and confounders (both of which should be minimized by randomization), possibly distorting

5025-404: The terms "single-blind", "double-blind", and "triple-blind"; instead, reports of blinded RCT should discuss "If done, who was blinded after assignment to interventions (for example, participants, care providers, those assessing outcomes) and how." RCTs without blinding are referred to as "unblinded", "open", or (if the intervention is a medication) " open-label ". In 2008 a study concluded that

5100-448: The three program components: health, education, and nutrition. In these areas, Progresa increased school enrollment, lowered incidence of disease in children, and increased growth for young children receiving nutritional supplements. In sum "in the central impact areas...the results [were] encouraging." According to the bulk of literature describing IFPRI-Progresa, the project was the first large-scale social policy evaluation implemented in

5175-422: The transition period to convince skeptical parties in the new administration of Progresa' effectiveness through personal contact, meetings, and media reports. Due to the IFPRI evaluations, Progresa gained political hardiness and funding sources, while evaluation became a codified part of Mexican social programming. Fox continued the program and expanded it significantly into urban areas. A loan for US$ 1 billion from

5250-491: Was conducted by James Lind in 1747 to identify a treatment for scurvy . The first blind experiment was conducted by the French Royal Commission on Animal Magnetism in 1784 to investigate the claims of mesmerism . An early essay advocating the blinding of researchers came from Claude Bernard in the latter half of the 19th century. Bernard recommended that the observer of an experiment should not have knowledge of

5325-417: Was divided between 'operational' evaluation (is the program being carried out according to the design?) and 'impact' evaluation (is the program having the intended effect on the target population?). Without discounting the importance of the operational evaluation, the data focuses exclusively on impact evaluation, which received far greater attention and had a much broader audience. The impact evaluation involved

5400-686: Was made generally available through the Internet. Secondly, information was provided to Congress and other government officials at all levels in the form of detailed budget proposals, program evaluations, and other relevant documents. Finally, public relations campaigns were initially minimal to avoid raised expectations. However, since 2006, the public profile of the program has been raised, particularly through extensive radio and television advertisements. Traditionally, most anti-poverty programs in Mexico have relied on presidential support to establish their funding and public profile. Although Oportunidades originally

5475-426: Was no different in its dependence on Zedillo to support its startup costs, much effort has since been made to establish an image of Progresa-Oportunidades as independent of the president and national party politics, in order to heighten chances it would survive transfers of power in the executive branch. Several congressional provisions have helped to ensure this identity. Among these are several provisions that prevent

5550-596: Was received." Unlike allocation concealment, blinding is sometimes inappropriate or impossible to perform in an RCT; for example, if an RCT involves a treatment in which active participation of the patient is necessary (e.g., physical therapy ), participants cannot be blinded to the intervention. Traditionally, blinded RCTs have been classified as "single-blind", "double-blind", or "triple-blind"; however, in 2001 and 2006 two studies showed that these terms have different meanings for different people. The 2010 CONSORT Statement specifies that authors and editors should not use

5625-532: Was that the aircraft were parked on the ground, and participants had only jumped about two feet. RCTs are considered to be the most reliable form of scientific evidence in the hierarchy of evidence that influences healthcare policy and practice because RCTs reduce spurious causality and bias. Results of RCTs may be combined in systematic reviews which are increasingly being used in the conduct of evidence-based practice . Some examples of scientific organizations' considering RCTs or systematic reviews of RCTs to be

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