Public Release: 

Why is conducting research in some countries so difficult?

Columbia University's Mailman School of Public Health

August 4, 2017 -- Low- and middle-income countries such as Brazil face a lack of epidemiological data, and one of the key priorities for researchers is developing high-quality surveys. Investigators at Columbia University's Mailman School of Public Health with collaborators at the Federal University of São Paulo studied the difficulties in conducting a longitudinal epidemiological survey in a school-based sample in Brazil. The findings are published online in the journal BMC Psychiatry.

"Overall, researchers in countries like Brazil lack the necessary funding resources to conduct important scientific research," said Silvia Martins, MD, PhD, associate professor of Epidemiology at the Mailman School of Public Health. "In particular, there are very few studies assessing the potential impact of social inequalities and exposure to traumatic experiences on psychiatric outcomes at the population level."

Martins and colleagues studied a sample school-attending adolescents born in 2002 now in the 7th grade in nine public schools during 2014 in two neighborhoods of in Sao Paulo with different levels of urbanicity. One neighborhood had low exposure to urban violence and scored high on the Human Development Index, while the other experienced high exposure to urban violence and low Index scores. In total, nine public schools located at the most socially vulnerable regions of each neighborhood were selected.

"At the start, we experienced several hardships," said Martins. "These included achieving unbiased sampling, reaching subjects, scheduling interviews, keeping participants' updated contact information, and counting on a highly-trained research team."

Some classes' records contained names of students who had never actually studied in those schools. "Inaccurate lists of enrolled students were a major source of concern," noted Martins. In terms of communications, the researchers found that poor internet access, deficient telephone and postal services also affected results.

"Our study offered some important insights on the problems faced when conducting epidemiological field work in low- and middle-income countries and provides some alternatives on how to deal with these difficulties. Working closely with community leaders, organizing group efforts to perform interviews, using a short, easy to understand instrument and providing a reward for participants are some of the strategies to be used, not only in Brazil, but also in other low- and middle-income countries," observed Martins.


The study was supported by Columbia University President's Global Innovation Fund.

Co-authors are Shannon O'Healy, Mailman School of Public Health; Thiago Fidalgo, Zila Sanchez, Sheila Caetano and Marcos Ribeiro, Federal University of São Paulo.

Columbia University's Mailman School of Public Health

Founded in 1922, Columbia University's Mailman School of Public Health pursues an agenda of research, education, and service to address the critical and complex public health issues affecting New Yorkers, the nation and the world. The Mailman School is the third largest recipient of NIH grants among schools of public health. Its over 450 multi-disciplinary faculty members work in more than 100 countries around the world, addressing such issues as preventing infectious and chronic diseases, environmental health, maternal and child health, health policy, climate change & health, and public health preparedness. It is a leader in public health education with over 1,300 graduate students from more than 40 nations pursuing a variety of master's and doctoral degree programs. The Mailman School is also home to numerous world-renowned research centers including ICAP and the Center for Infection and Immunity. For more information, please visit

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