First, is the Protestant work ethic still a useful category in modern industrialized societies?
For identifying such features, the traditional figures of speech (schemes and tropes) are often useful categories.
Some anthropologists, particularly forensic anthropologists, consider race a useful biological category.
The extensive bibliography is grouped into useful categories, and there are photographs and maps.
There is no accurate profile of the school shooter, but there are several useful categories.
Mr. Tower's consulting experience belongs in a less useful category.
In this stage, condensing large data sets into smaller units permits further analysis of the data by creating useful categories.
It's interesting, but 'raised outside the traditional two parent family' isn't a very useful category.
Cameron's four headings are, however, useful broad categories into which might fall the examples chosen for this paper.
To Warlock, people were divided into two basic categories: useful and irrelevant.