Science

How to Use the Word “Respectively” in a Scientific Paper

The word “respectively” appears often in the medical and scientific papers that I edit. Unfortunately, authors often misuse the word.

According to the online edition of the Merriam-Webster Dictionary, “Respectively” has two definitions:

1in particular separately

  • could not recognize the solutions as salty or sour, respectively

2in the order given 

  • Mary and Anne were 12 and 16 years old, respectively

We rarely encounter examples of the first definition in written English. As the definition implies, it’s more common and acceptable to write “in particular,” or “separately,” as in “In particular, Dr. Lindeman could not recognize the solutions as salty or sour” (this happens to be true, but that is a subject for another post).

The second definition describes the most common reason to use the word “respectively.” That is, to relate a list of names or parameters to some value, usually numeric data, and the writer wishes to indicate that the list of values follows in the order given for the names or parameters. It’s best to illustrate this concept with examples:

  • The mean, median and range of ages of my children are 18.3, 18, and 17-20, respectively.
  • The Yankees, Red Sox and Rays are in first, second and third place, respectively.
  • The overall survival and disease-free survival rates for the control group were 10.8 and 5.3 years, respectively.

There are a couple of points to note with these examples. The first is that the main verb in each sentence is plural in number: “…my children are…” “… and Rays are…”, “…control groups were…”. This is always the case in sentences using the word respectively.

The second thing to notice is that the word “respectively” is at the end of the sentence, set off by a comma. In modern standard written English, this is the accepted convention. You can place the word elsewhere in the sentence, but I believe you make the sentence much more difficult to understand.

The final thing to notice is that the first two could be easily re-written without the word “respectively.”

  • The mean age of my children is 18.3 (range 17-20), and the median age is 18.
  • The Yankees are in first place, the Red Sox are in second place, and the Rays are in third place.
  • For the control group, the overall survival rate was 10.8, and the disease-free survival rate was 5.3.

Even though this formulation may require more words, they convey the same information, and the reader has no trouble understanding what the author meant.

My recommendations for using the word “respectively” are as follows:

  1. Don’t use it if you don’t have to. It only makes the job or reading your paper more difficult!
  2. If you must use it, do so when you are joining a list of things at the beginning of the sentence with stuff at the end.
  3. Always set the word “respectively” off by a comma at the end of the sentence.

 

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