December 13, 2016
Dr. Kathryn Sobek, Filipodia Editor
The word ‘respectively’ is an adverb used to enumerate two or more items that refer to a previous statement. The use of this word requires parallelism, meaning each item must correspond to one separate item in the previous statement.
Correct: The values of ‘x’ and ‘y’ were 20.3 and 16.8, respectively. (It is clear that x = 20.3 and y = 16.8)
Incorrect: The two values were 20.3 and 16.8, respectively. (There is ambiguity as to what the values correspond to).
Correct: Expression of caspase-8, caspase-9, and Bcl-2 were measured 30 minutes, 45 minutes and 60 minutes after the treatment, respectively.
Incorrect: The three proteins were measured 30 minutes, 45 minutes, and 60 minutes after the treatment, respectively.
There are also instances where the use of respectively is not required.
Incorrect: The value of ‘x’ was 20.3, and the value of ‘y’ was 16.8, respectively. (Respectively is unnecessary because the value is already stated immediately after the parameter.)
Correct: The value of ‘x’ was 20.3, and the value of ‘y’ was 16.8.
Incorrect: Expression of p53 was identified in breast cancer and prostate cancer, respectively.
Correct: Expression of p53 was identified in both breast cancer and prostate cancer.