Question

A 2001 study by two researchers investigated an anti-poverty initiative in Venezuela called POVERTA. POVERTA gave money to poor families, but required as a condition for payment that the families participate in a range of programs to improve their health and education. The amount of money POVERTA gave to participating families was substantial, increasing participating families' income by a factor of roughly 1/3 on average. POVERTA eventually covered families in around 50,000 Venezuelan communities, but the program's managers initially evaluated it using a smaller group of 505 communities selected to have similar poverty levels. Out of those 505 communities, the managers randomly chose 320 to receive POVERTA benefits in the first two years of the program (1998 to 2000). Families in the remaining 185 communities (out of the 505 selected) received no benefits in the first two years. The researchers focused on the impacts of POVERTA on health. They measured various health-related outcomes for the 505 communities and found that children in the 320 communities that received POVERTA benefits had substantially lower average rates of illness than children in the other 185 communities when the two-year period ended. 1. Was this an observational study or a randomized controlled experiment? 2. Did this analysis have a treatment group and a control group? If so, describe the two groups 3. Does the study provide evidence that being in a community receiving POVERTA benefits is associated with a lower rate of childhood illness? 4. Does the study provide evidence that being in a community receiving POVERTA benefits causes a lower rate of childhood illness? 5. Most families eligible for POVERTA participated in the required health programs, but around 3% did not. (Those families were unwilling or unable to participate. This study did not investigate the reasons for non-participation.) Suppose we limit our study to the 320 eligible communities, and within those communities we compare the health outcomes of the families that participated (and received POVERTA money) with those that did not (and therefore received no POVERTA money). Would that analysis constitute an observational study, a randomized controlled experiment, or neither?

Answer 1

1. This is a "RANDOMIZED CONTROLLED EXPERIMENT".

A randomized controlled experiment is a type of research study, were the researcher randomly select samples in other not to be biased. This samples are separated into two groups, which are the experimental and the controlled group.

2. The research has a treatment group and a controlled group.

A treatment group are those group that received some special treatment from the researcher, it can also be called the experimental group. According to the research, the treatment group are those who are in the POVERTA scheme. That is the 320 communities.

A controlled group are those group that were not given any special treatment, but are , separated and studied. According to the research the controlled group are those 185 communities

3. This research provides evidence that being in a community receiving POVERTA benefits is associated with a lower rate of childhood illness. Because after two years, it was noticed the children in the community that receives POVERTA has low rate of illness, than the children in a community that doesn't receive the benefits of POVERTA.

4. This study does not provide evidence that being in a community receiving POVERTA benefits causes a lower rate of childhood illness. Because the research did not involve treatment of illnesses and they is no experimental evidence that shows that POVERTA benefits is interrelated with illness, as illness involves the internal functions of human body.

5. Such study will be called a "RANDOMIZED CONTROLLED EXPERIMENT". Because their randomly isolated themselves, and the POVERTA treatment was not given to them. The researcher was not based in selecting them not to participate.