Buried deep into an article on keyword research I found this caution:
Our only complaint with Overture is that they lump singular and plural word forms into one phrase. For example, “boots” and “boot” would appear under one category of “boot”. This can sometimes cause problems.
I’m not sure why this causes problems. The search engines look for phrases that are searched for often. Since the word “boot” appears within the word “boots,” it only makes sense that searches made for “boots” would turn up results for “boot.” But not the other way around.
Maybe this is what the author means by “causes problems.” But to me that’s not a problem. It’s a blessing.
If 100,000 searchers search for the keyword “boot” while 180,000 search for “boots” then I can assume that approximately 80,000 of the searchers are searching for “boots” specifically as opposed to the singular “boot.” I’m quite certain that 100,000 of that 180,000 searching for “boots” are looking for the singular form. The only problem is, How good is your math?
These are general numbers, of course. The search engines may or may not turn up every reference to the terms. Overture may not find every reference either. I once conducted an experiment with a friend of mine. We each searched for the exact same term on Google at the same time. His search returned almost 100,000 results more than mine did. Why? Because our searches were conducted on different servers. Therein lies the biggest problem with keyword research.
Because every Internet user will, at any time, conduct a search on a different server than any other user, there will always be some disparate nature to numbers. In a word, no number can be relied upon entirely. Therefore, whether you choose to use numbers for the singular form of a word or a plural form is not much of a point. I’d rather use the numbers for the singular because then I know I’m getting most of the searchers for the plural as well, but that is not the case for vice-versa. Just remember one thing: Keyword research is not exact science.