An interdisciplinary team of researcher led by an assistant professor of biology and evolutionary ecology at Princeton University in the US explored multiple, far-ranging explanations for the spectacular diversity in the size and shape of eggs produced by birds. The fact that eggs with pointy ends are less of likely to fall out of the nest offered an explanation for cliff dwelling birds, but did not explain global patterns. Similarly, other explanations generated by the team characterized one species, but did not extend to others. Round eggs, for example, benefitted bird populations with large clutches of eggs.
This situation has relevance to the mixed methods researcher that finds him/herself trying to explain discordant data. Sometimes a definitive result is arrived at through blind luck or poking around (a.k.a. “fishing).In a recent publication, my co-author, Cherie Edwards, and I highlighted the potential for theory development that can lie in pursuing multiple possible explanations through additional data analysis.
Concluding that their results reinforce that natural selection favors diversity, the authors found that one of the best predictors of egg shape is flight ability and wing span, with long distance fliers, like the wandering albatross, tending to lay long or pointy eggs while short distance flyers, like an owl, that fly in short bursts, having rounder shells.
For an overview of key features of the philosophy and procedures for mixed method research, see A Primer About Mixed Methods Research in Educational Contexts.