Only a fool would argue against the proposition that barriers are important in determining the outcomes of races.
As GT has said there are a stack of caveats that must be considered, e.g. the distance, the starting point at the track in question, and the condition of the track, the field size, the rail position.
Lots of sites, publications, etc, put up barrier stats. But in the main they're not worth the space they occupy (because they don't deal with the points above).
The size of the field is typically not taken into account. I mean, barrier 10 obviously can't win if it's not occupied. It's a mammoth exercise though, to produce tables that DO mean something.
A reasonable simple statistic that can now be calculated with the aid of a computer is the performance of the inside half of the stalls relative to the outside half.
Say it's a 10 horse race at the 1810 at EF ...total the finishing positions of the horses drawn 1-5, and compare it with that of the horses drawn 6-10. If the barriers have no influence, the scores should be approximately equal at around 27.
Over time you'll then build up a profile for the particularly starting point (by adding up the inside totals and outside totals). No problems with odd-numbered field sizes (e.g. 11). You either toss them out - it won't alter the end result - or put half the score to both sides.
You might end up over time for the 1810 at EF with a score of 55 vs 45. It's then up to you to dedcide on the significance of the difference.
Definitely worth doing if someone has the results, and computer skills.
On stuff I've done years ago, you'll be surprised at the results with big fields at the majority of barrier starts in Brisbane. The outside barriers are nowhere near the problem that most of us believe.