Lisa Bowleg and colleagues’ mixed methods research on Black Lesbians warns of the implications of using social categories such as race, ethnicity, sex as additive variables.

In reflecting on her own methodological choices, Bowleg concludes that when you ask research questions that frame separate linked dimensions of a person’s identity, you will get additive answers. This has two implications: the answers have “limited ability to explain how different social categories intersect with each other to shape people’s experience; and they don’t offer insights into the root causes of inequalities.

Bowleg provides the following example of an additive approach to questioning from her own qualitative research:

“… If someone dropped in from another planet and asked you to tell them about your life as a Black lesbian woman, what would say about your life as a Black person? Woman? Lesbian? and Black lesbian woman?”

Similarly, in the quantitative element of her research, participants were given the option of using a five-point Likert type scale (1 = strongly agree, 5 = strongly disagree) to indicate the extent to which they agreed or disagreed with statements such as: “Racism is a much more serious issue in my life than homophobia” and “Racism is a much more serious issue in my life than sexism”.

Bowleg argues that the commonest approach to measuring intersectionality is inherently additive involving respondents “checking all [variables] that apply” is inadequate as none of the options given are ideal. As she says:

“It is obvious now in retrospect that a truly intersectional question would simply ask the respondent to tell about her experience without separating each identity.”

Karen, one of her research participants sums it up in her response to the question about her life as a Black or African American woman?: “Well, you probably could combine all those statements”

Ashlee Christoffersen (2017) of the Equity Challenge Unit cites Bowleg’s work in her guidance on integrating an intersectional equity lens into research. She argues that researchers shouldn’t assume that one equality area alone will provide an explanation for an experience of inequality and that questions that ask people to rank or separate out aspects of their identity should be avoided.  So instead of asking “Do you think that your race or your gender influenced your experience of the recruitment process?” she suggests asking “Do you think that your identity influenced your experience of the recruitment process?”