Why do review pages rank lower on U.S. Google servers?

[irock]

Hi, I run a review site that focuses primarily on <widgets> and try to target as many U.S. visitors as possible.

However, I notice since April 2010 my pages, particularly product reviews, rank lower on U.S. Google servers than other server locations. I know it's been a while and a lot has happened but this 'problem' still continue to frustrate me. It seems more U.S. retailers have occupied the top 10, yet I still see a good number of competitors whose ranks aren't affected.

All my reviews are original and professionally written. Each of them is between to 1600 to 2800 words long.

If anyone knows there's a fix for this or has similar experience, pls share. Thanks for all your help.

[edited by: Robert_Charlton at 4:57 am (utc) on Apr 30, 2012]
[edit reason] removed specifics [/edit]

[Robert Charlton]

US Google serps are generally more competitive than foreign serps.

Inbound link location can also affect ranking in different geo-areas. Check to see whether your inbound links are coming from the US. If too many are from out of country, that could adversely affect US rankings.

If your site is hosted outside of the US, that might also send signals to Google that could hurt US rankings.

[Planet13]

One Thing: Does google give preference to sites where there is MORE THAN ONE AUTHOR creating the reviews of the products?

I know that google has a way of telling how many authors there are contributing to blogs (I believe they only list sites with multiple authors in the google news section), so I wonder if multiple contributors helps boost review sites?

[irock]

Thanks for your reply Robert.

So, during Panda update, I deleted a whole bunch of articles (over 300) that are heavily linked by very large U.S. sites. (My site has about 500 pages). Do you think bringing back those articles (either in its original or re-written form) can give my ranking a boost?