The Correct way to use Respectively in a Sentence
What is “respectively” used for?
The word “respectively” can be used to clarify links between multiple separate words in a statement in scientific writing. It is used to convey to the reader that the link between two groups of words or phrases can be interpreted in terms of their appearance order.
What the AP Style Manual recommends
The AP Style Manual requires authors to include a comma before the word “respectively” at the end of a sentence when making a parallel comparison between multiple items. However, they do not view it as mandatory at the moment. So this is a matter of personal preference, as long as there is consistency throughout the writing.
Respectively and its commas are being seen identically to the Oxford comma. A while back, a comma was required following the third or subsequent item in a series of three or more. With time, AP had eliminated that criterion, unless the comma was absolutely necessary for clarity, like in an expression of multi-word statements. As a result, a growing number of writers are abandoning the commas for “respectively” when clarity is not a concern. Some have abandoned the term entirely.
The guidance given in style manuals varies. If you are not forced to adhere to a style guide, however, let clarity be your guide. When the corresponding items are mapped clearly, you do not need a comma.
Examples of respectively at the end of a sentence
With a comma: The accuracy obtained by Model 1 and Model 2 was 88% and 90%, respectively.
Without a comma: The accuracy obtained by Model 1 and Model 2 was 88% and 90% respectively.
(Both examples are correct.)
Examples of respectively in the middle of a sentence
When respectively is used in the middle of a sentence, it requires a comma.
Example: The accuracy obtained by Model 1 and Model 2 was 88% and 90%, respectively, and these results are depicted in the figure.