Serial Comma/ Oxford Comma

The serial comma, also known as the Oxford comma, is used to delineate the last item in a list. Here is a silly example:

For lunch I had a sandwich, chips, and a soda.

The comma right after “chips” is the serial comma.  In engineering, technical, and scientific writing, the use of this comma is essential because in these fields, ambiguity can be hazardous, costly, and confusing (if not irritating). The use of the last comma tells any reader that the last two items are discrete items, not a set of two. The elimination of that last comma can potentially produce disaster.

Example:  For the lab, we need hydrogen perioxide, calcium, rubidium and distilled water.

(If you don’t know what the issue is here, look up “rubidium and water” on YouTube. You don’t want any colleague unfamiliar with these chemicals to put rubidium and water together!)

Thus, we advise for all engineering, technical, and scientific writing that you habitually use the serial comma. Deploying that simple comma is always grammatically correct, even if stylistically it could be challenged.  In truth, it’s not worth thinking about; just use it.

Example 1:

Proposed modifications include adding a chain tensioner to minimize chain slack, to add rib supports to prevent flexion of the support platform, and to use stronger materials to minimize compliance between individual components. 

Example 2:

However, this practice exposes the product to high concentrations of O2, greater changes in temperature and humidity levels, and the risk of elevated concentrations of C2H4.