There seems to be a growing recognition that migration is not only a vital topic in development, but one that is also difficult to understand because of the many factors that drive people's movements.
Last month, SciDev.Net reported that the UN University recognised the complexity of research into migration and, in response, launched a migration network designed to facilitate an interdisciplinary approach to its study.
I spotted a paper in the open access journal PLOS ONE which seemed to underline the difficulties with migration research. The paper was on mental health interventions in migrant communities - not an area that gets much airtime, but another reminder that a truly diverse range of disciplines are relevant to the study of migration. 
I called one of the study's authors, Mina Fazel, to hear more about the role of mental health in migration research. Fazel, a psychiatrist at the University of Oxford, United Kingdom, says she began her study because she wanted to know how various types of mental health interventions - from creative arts therapy to counselling - could help refugee children deal with past experiences.
"Often these children have been through difficult times," Fazel tells me, "so it's important to do studies like this so as to inform humanitarian agencies about what works to help them deal with that."
Fazel's study compared 19 published trials of mental health interventions carried out in schools and communities in several different countries, including Canada, Iran, Sri Lanka, and Uganda. But this comparison was tricky because the researchers behind each trial came at the issue from a different angle, each with their own methodology. Some looked at just one type of intervention, while others were 'multimodal': they tested several approaches at once.
The big differences between the studies meant that they could not be combined in a meta-analysis, a powerful way of merging evidence from multiple sources to get deeper insights.
"We should be aiming for a meta-analysis," says Fazel, explaining that having a series of studies done using similar methodology would be a potent way to accumulate evidence on the effectiveness of particular interventions.
"But that doesn't mean we have to limit our research to single issues," she says. "What I'd like to see is more research that looks at holistic ways of intervening for mental health. That's pretty reasonable, since that is what it's really like to deal with refugee children's mental health in this way - you don't just use one approach."
 Rebecca A. Tyrer and Mina Fazel School and community-based interventions for refugee and asylum seeking children: a systematic review (PLOS ONE, 24 February 2014)