# Difference between the use of "for" and "of"

I am always confused by the difference between the use of for and of in cases like these:

1. Principal component analysis of microarray data.
2. Principal component analysis for microarray data.

Which of these is correct? Is it OK to use both? If yes, when should I use 1. and 2., respectively?

• It would help if you provided complete sentences as examples. It would also help if you simplified the jargon. Commented Dec 24, 2010 at 4:23
• @John Satta. Sorry, I thought the jargon would not matter. Commented Dec 24, 2010 at 8:19

## 1 Answer

Both examples are correct usage, but the meanings are different and very much dependent on the context.

If the microarray data is being analyzed, then "of" is used to indicate relation.

To better understand the results, we must perform a principal component analysis of the microarray data.

If the microarray data is the outcome of the analysis, then "for" is used to indicate attempting to obtain, gain, or acquire.

We suspected the flux capacitor might contain microarray data, so we decided to perform a principal component analysis (of the flux capacitor to search) for it.

Where "it" is the microarray data.

Another pair of simpler examples:

If we seek the maguffin, then we might

search his luggage for the maguffin

If we suspect kryptonite is hidden within the maguffin, then we might

Perform a search of the maguffin seeking kryptonite

• Great! That's exactly what I was looking for. Thank you very much. Commented Dec 24, 2010 at 8:22
• Just to clarify: microarray data is a special kind of data and principal component analysis is a method of analyzing it. I hope I used it correctly :-). Commented Dec 24, 2010 at 8:26
• @suncoolsu - You're welcome. Then in your case, analysis of data is the best usage Commented Dec 24, 2010 at 13:39