A manual for writers of research papers, theses, and dissertations, 7th edition - Kate L. Turabian 2007

The stub
Tables and figures
Part III. Style 20 spelling

The leftmost column of a table, called the stub, lists the categories of data in each row.

Include a column head for the stub whenever possible, even if it is generic (“Typical Characteristic” or “Variable”). Omit the head only if it would merely repeat the table title or if the categories in the stub are too diverse for a single head.

Make stub entries nouns or noun phrases whenever possible, and keep them consistent in form: “Books, Journal articles, Manuscripts” rather than “Books, Articles published in journals, Manuscripts.” Use the same word for the same item in all of your tables (for example, if you use Former USSR in one table, do not use Former Soviet Union in another).

Capitalize all stub entries sentence style (see 22.3.1), with no terminal periods.

Set the stub head and entries flush left, and indent any runovers (as in table 26.1).

To show the sum of the numbers in a column, include an indented stub entry entitled Total (see table 26.2).

If the stub column includes subentries as well as main entries (see table 26.3), distinguish them through indentation, typography (such as italics), or both. Follow the same principles listed above for main entries for capitalization and so forth.