LSE’s Femke Gubbels describes the snowball sampling technique proved useful while doing research in Tanzania.

Participant sampling techniques are of relevance to any study involving human subjects. The options are myriad and choosing the right one hinges on what your research is trying to uncover. When conducting research guided by ethnographic principles, it is not uncommon to use snowball sampling; asking someone (a respondent or an acquaintance) who knows others who meet your study requirements to refer you to them. This technique can be particularly helpful when you are new to a field and are trying to get the interview ball rolling.  As a researcher you might like to believe you are in control of your sample, but sometimes the sample takes control over you. So the question is; if you throw a snowball, should you be prepared to catch it all times?

A stranger to Dar es Salaam, I knew I would have to rely on connections of my network to be able to access certain respondents whose views I wanted to hear. After initial meet ups and informal conversations, it became clear that people generally seemed interested in the research topic and were very generous in spending some of their time to talk to me – and connect me to other organisations or key individuals. Besides ‘snowballing’, another non-random sampling method I employed was approaching people on the streets near their houses. The environment provided an entry point for conversation. As I am looking at adaptation to flooding, talking to people around or in their houses was helpful as it allowed them to point out –for example- how high the water comes when it floods, which objects they move, what they have done to ‘flood-proof’ their houses, and other identifiable place-based practices.

Towards the end of my time in the field, I received multiple texts on my Tanzanian sim by a person unknown to me, requesting me to pay him a visit for an interview. He presented himself as part of a community group addressing environmental issues in an area adjacent to the site of my focus. Admittedly I couldn’t help but feeling (overly) excited that somehow word on the street got out that I was doing research on issues he was keen to discuss, and subsequently managed to get my contact details – most likely through a snowball thrown and caught without me knowing.

So on a given morning, after completing some observations in my area of research and asking for needed directions, I hopped in a bajaji with my research assistant to find the person who I had been texting with to agree on time and location (uncovering his messages with the invaluable help of Google Translate and my research assistant – many thanks to both). We ended up talking for a few hours and meeting other local individuals who kindly showed us around the neighbourhood, pointing out infrastructural deficits that exacerbate the impact of floods.

The community group had been actively attempting to draw attention to the environmental injustices they face living on low-lying hazardous land; a nearby brewery disposing waste into public water outlets, lack of maintenance of drainage infrastructure, international organisations denying support as the government does not work in the area, and appealing to court cases for proposed demolitions were only a few of the concerns the community group addressed.

In many ways this visit was extremely helpful for my research. But the community group also expressed their hopes for me to practically support them in their struggle – something I have only very limited capacity to do. This is a part of snowball sampling that is not frequently discussed: How are you introduced and consequently manage expectations when someone refers you to their network? And should you, out of courtesy to their efforts, always follow up on snowball leads even when you believe you can spend (often limited) time in the field more effectively?

I don’t believe I have an answer to these questions as they are inherently context-specific. Snowball sampling offers many benefits but also has its limitations; not knowing how you are introduced by your referrals is one of them. Nonetheless I find snowballing a useful way of reaching out to people. Who you are referred to also discloses something about the person doing the referring and can provide helpful insights into exploring networks. So for now I will continue to stay involved in the snowball business, and be prepared to both throw and catch if needed.

This article was first published on the Everyday Dar blog.

Femke Gubbels is a masters candidate in LSE’s Department of Geography and the Environment. Follow her on Twitter @femke_gubbels.

The views expressed in this post are those of the authors and in no way reflect those of the Africa at LSE blog or the London School of Economics and Political Science.