This is certainly an interesting topic. I'd love to see some comparison made between past/upcoming titles too, as I think that could give us some extra insight. Just something off the top of my head would be this: CoD MW2 vs Halo Reach (using Halo 3/Halo 3 ODST ratios as a loose guide).

First week sales for Halo 3/ODST were roughly 3:1 in favour of Americas compared to EMEAA (Halo 3: 2.8m vs 0.9m, ODST: 1.67m vs 0.5m). In comparison, first week sales of CoD MW2 (on 360) were 2:1 in favour of Americas compared to EMEAA (3.28m vs 1.6m).
For (American, as that's what we get) preorders, MW2 finished at approximately 1.85m I believe (I can only find 1 week before, where it was at 1.7m with a week to go, so I'm approximating). We can see that sales of MW2 in Americas were ~72% higher than preorders. For ODST, preorders totaled 1.35m, which meant that total sales (in Americas) were only about 23% higher than preorders. I can't seem to find pre-order numbers for Halo 3, so it would be great if someone could find them for me.

Based on these figures, it would seem to suggest that Halo sales are more pre-ordered than other blockbusters (though ODST was widely seen as an expansion pack, so it's also not surprising that only the more "dedicated" would appear to have purchased, and many of those would be more likely to pre-order than the more "casual" gamers). While it's hardly an exact science, this to me gives the impression that while Halo Reach may have more American pre-orders than MW2 (on Xbox 360), it is quite possible that the number of non-pre-ordered copies will be lower. Similarly, sales in EMEAA are likely to be lower than American sales for Halo Reach, in relative terms at least when compared with many other large franchises. As I've said, these are all estimates, but I just think it is interesting to look at. It's things like these (Halo being far bigger in Americas than EMEAA compared with other titles, pre-orders for Americas as such making up a larger portion of overall first-week sales than other titles), that leads me to believe that Reach is unlikely to beat MW2's (360) first week sales worldwide. All just food for thought, and definitely only a theory, but I thought it might be something you guys might all be interested in.

EDIT: So, I think my actual point was that it would be interesting to see sales of previous entries in franchises (for example, Fifa 10 pre-orders/sales ratio to see how Fifa 11 might end up), and I just went into far too much detail with my example.

You really shouldn't do a ratio between America's pre-orders and WW week 1 sales because there's no record of pre-orders for the rest of the world, which means the ratio is distorted and doesn't truly reflect the pre-order to Week 1 sales sell through.

For instance Madden's ratio looks like crap compared to Mafia II's. But in the America pre-orders vs America week 1 ratio Madden's ratio is better than Mafia II's. Clearly Mafia II had reasonable pre-orders in other countries, whereas Madden probably had almost none.

This is certainly an interesting topic. I'd love to see some comparison made between past/upcoming titles too, as I think that could give us some extra insight. Just something off the top of my head would be this: CoD MW2 vs Halo Reach (using Halo 3/Halo 3 ODST ratios as a loose guide).

First week sales for Halo 3/ODST were roughly 3:1 in favour of Americas compared to EMEAA (Halo 3: 2.8m vs 0.9m, ODST: 1.67m vs 0.5m). In comparison, first week sales of CoD MW2 (on 360) were 2:1 in favour of Americas compared to EMEAA (3.28m vs 1.6m).
For (American, as that's what we get) preorders, MW2 finished at approximately 1.85m I believe (I can only find 1 week before, where it was at 1.7m with a week to go, so I'm approximating). We can see that sales of MW2 in Americas were ~72% higher than preorders. For ODST, preorders totaled 1.35m, which meant that total sales (in Americas) were only about 23% higher than preorders. I can't seem to find pre-order numbers for Halo 3, so it would be great if someone could find them for me.

Based on these figures, it would seem to suggest that Halo sales are more pre-ordered than other blockbusters (though ODST was widely seen as an expansion pack, so it's also not surprising that only the more "dedicated" would appear to have purchased, and many of those would be more likely to pre-order than the more "casual" gamers). While it's hardly an exact science, this to me gives the impression that while Halo Reach may have more American pre-orders than MW2 (on Xbox 360), it is quite possible that the number of non-pre-ordered copies will be lower. Similarly, sales in EMEAA are likely to be lower than American sales for Halo Reach, in relative terms at least when compared with many other large franchises. As I've said, these are all estimates, but I just think it is interesting to look at. It's things like these (Halo being far bigger in Americas than EMEAA compared with other titles, pre-orders for Americas as such making up a larger portion of overall first-week sales than other titles), that leads me to believe that Reach is unlikely to beat MW2's (360) first week sales worldwide. All just food for thought, and definitely only a theory, but I thought it might be something you guys might all be interested in.

EDIT: So, I think my actual point was that it would be interesting to see sales of previous entries in franchises (for example, Fifa 10 pre-orders/sales ratio to see how Fifa 11 might end up), and I just went into far too much detail with my example.

Well until we get European pre-orders and whatnot this is the best I can do.

The best you can do until we get Worldwide pre-orders, in terms of mathematical integrity, is for your ratio to be Americas Week 1:Americas pre-orders.

If you get Europe and America and still do a ratio with WW week 1 sales then it would still be a non-rational ratio, especially for a game that does particularly well in Japan (RE5, MGS4, NSMB Wii, GT5[no doubt]). Outside of Europe, Americas and Japan there are about 10 million PSWii360's. While not a huge % of the market it can still have a distorting effect on numbers.

Of course America's Software sales numbers are also not completely related to the pre-order chart given VGC weekly data is for Nth and Sth America whereas the pre-order chart is for North America only (does it include or exclude Canada). I guess for data approximation it would be best if the America's week 1 sales were reduced by about 18% (what the Source does to estimate / compare with NPD). That would be about as close to accurate for sales:pre-order as you could get I think.

What you're doing is great, and the more interesting data I get to see on this site the better. So I totally support what you're doing and appreciate the effort you're putting in to it. I was going for constructive criticism, trying to help improve your good work. Apologies if it didn't come out that way.