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RCTs

Helping poor women grow their businesses with mobile savings, training, and something more?

Mayra Buvinic's picture

Growing a business is not easy, and for women firm owners the challenges can be acute, especially when they are poor and run subsistence level firms. In developing countries, 22 percent of women discontinue their established businesses due to a lack of funds, and women are more likely than men to report exiting their businesses over finance problems, according to the Global Entrepreneurship Monitor. Meanwhile, personal savings are a crucial source of entrepreneurial financing, and nearly 95 percent of entrepreneurs globally state that they used their own funds to start or scale up their businesses. Women, however, face unique constraints in accumulating savings to invest in growing their firms.
 

Photo credit: Marijo Silva and the “She Counts” global platform.

What should you do when your random assignment gets compromised?

David McKenzie's picture

The New York Times recently had a piece on the retraction and re-issuance of a study in Spain based on a randomized trial of the Mediterranean Diet’s effect on heart disease. The original study was meant to be an individualized random assignment of 7,447 people aged 55 to 80 to one of three different diets – a control diet (advice to just reduce fat content), or two variants of the Mediterranean Diet (in which they were given free olive oil or free nuts). The study was originally published in the New England Journal of Medicine (NEJM) in 2013. The authors then appear to have been surprised to find their study on a list of suspicious trials.  There are several parts to this story I thought would be of interest for doing impact evaluations in development, which I discuss below.

Incorporating participant welfare and ethics into RCTs

Berk Ozler's picture

One of the standard defenses of an RCT proposal to a skeptic is to invoke budget and implementation capacity constraints and argue that since not everyone will get the desired treatment (at least initially), the fairest way would be to randomly allocate treatment among the target population. While this is true, it is also possible to take into consideration the maximization of participants’ welfare and incorporate their preferences and expected responses to treatment into account while designing an RCT that still satisfies the aims of the researcher (identify unbiased treatment effects with sufficient precision). A recent paper by Yusuke Narita seems to make significant headway in this direction for development economists to take notice.

The importance of study design (why did a CCT program have no effects on schooling or HIV?)

Berk Ozler's picture

A recent paper in Lancet Global Health found that generous conditional cash transfers to female secondary school students had no effect on their school attendance, dropout rates, HIV incidence, or HSV-2 (herpes simplex virus – type 2) incidence. What happened?

Weekly wire: The global forum

Darejani Markozashvili's picture

These are some of the views and reports relevant to our readers that caught our attention this week.

Freedom on the Net 2016- Silencing the Messenger: Communication Apps Under Pressure
Freedom House
Internet freedom has declined for the sixth consecutive year, with more governments than ever before targeting social media and communication apps as a means of halting the rapid dissemination of information, particularly during anti-government protests. Public-facing social media platforms like Facebook and Twitter have been subject to growing censorship for several years, but in a new trend, governments increasingly target voice communication and messaging apps such as WhatsApp and Telegram. These services are able to spread information and connect users quickly and securely, making it more difficult for authorities to control the information landscape or conduct surveillance.

The limitations of randomised controlled trials
VOX/The Centre for Economic Policy Research
In recent years, the use of randomised controlled trials has spread from labour market and welfare programme evaluation to other areas of economics, and to other social sciences, perhaps most prominently in development and health economics. This column argues that some of the popularity of such trials rests on misunderstandings about what they are capable of accomplishing, and cautions against simple extrapolations from trials to other contexts.

Mind Your Cowpeas and Cues: Inference and External Validity in RCTs

Berk Ozler's picture

There is a minor buzz this week in Twitter and the development economics blogosphere about a paper (posted on the CSAE 2012 Conference website) that discusses a double blind experiment of providing different seeds of cowpeas to farmers in Tanzania.

It worked for you. Will it work for me?

Berk Ozler's picture

Following on David’s rant on external validity yesterday, which turned out to be quite popular, I decided to keep the thread going. Despite the fact that the debate is painted in ‘either/or’ terms, my feeling is that there are things that careful researchers/evaluators can do to improve the external validity of their studies.