Prob been done somewhere else but culdnt find out wen i searched.

Is there a single reason why the game to psp ratio is so low compared to other consoles e.g. less star games or are their multiple reasons, because psp game sales ~(apart from some weeks duing to new japense games releases) are usually (relatively) lower than e.g ps3 etc

Homebrew and Piracy pretty much answers your question.

Edit : But to explain futher alot of the Wii/DS demographic don't have inteligence/intereste (not saying they are stupid , just not neccaserily able/interested in how to pirate games for the DS/Wii) enough to want to pirate the DS/Wii , Piracy on the XBOX 360 will result in online play being impossible , Piracy on the PS3 is currently impossible. Using anectdotal evidence I know 5-10 people who own PSP's every single one of them pirate regardless of their background , it's just  so easy.

Well, there are many sales missing, especially in Europe, but it is generally thought that it is because people use its multimedia functions instead of just playing games on it

If you look at the US data you will see the attach ration between the DS and PSP is nearly the same.European data we dont have really reliable data except for UK.And in Japan the PSP games sell quiet well ,but it has fewer games and it hasnt managed to have 4-5 titles with enourmous legs (to the point they keep selling 3 years later) as the BT,Mario Kart and New Super Mario games.

oh thanks i understand now

i stopped playing games on PSP since.......i cant remember, maybe a year ago.

I use it as portable MP4 player now.

The attach ratio you see on the American and Japan data will be pretty good in accuracy terms, but the attach ratios (for all systems) on the European data are not very accurate because many games are missing data.
The PSP is the one most affected by this because it's games rarely sell high in the charts anyway, so PSP has the highest percentage of games missing from European data. (360 and DS will be next, then PS3 and Wii are least affected)

Generally PSP has a lower attach ratio anyway, partly because it is a handheld (which usually have lower ratios in all regions, though DS in Japan is breaking this) and partly because of piracy, and partly because of the game library, most PSP games have similar experiences to PS2 games, with a few exceptions.

Still, the major factor is that PSP is by far the most heavily affected platform in terms of European games tracked.

Idd, he summed it up pretty nice. Allthough PSP sales are also more affected by piracy than DS for instance. Cause it's too easy to hack the PSP. Allthough I'm still proud that mine isn't and won't be. On DS you have to do more. Buy a card in order to get the thing set and ready for illegal stuf... Somehow a large group doesn't know it or doesn''t want to know that and keeps buying games. :)

 Or they are just way to young to know the procedure to hack a system :P