Much discussion among researchers centers around defining and measuring two key but related variables: ethnicity and diversity. It is debated whether ethnicity should be defined by culture, language, or religion. While conflicts in Rwanda were largely along tribal lines, Nigeria's string of conflicts is thought to be – at least to some degree – religiously based. Some have proposed that, as the saliency of these different ethnic variables tends to vary over time and across geography, research methodologies should vary according to the context. Somalia provides an interesting example. Due to the fact that about 85% of its population defined themselves as Somali, Somalia was considered to be a rather ethnically-homogeneous nation. However, civil war caused ethnicity (or ethnic affiliation) to be redefined according to clan groups.