Good point bt. I always take into account the barrier of the previous start and most importantly the field size.
However you also have to check the run the horse enjoyed. Barrier 1 is not a good barrier for a slow beginner as they often get buried 6 back on the rail and need the leaders to all leave the rail to get a run up the inside... or peel 4 or 5 deep in the straight.

Alternatively a brilliant beginner can draw wide in a large field and still be in front before the first bend.

In my opinion the main things to look for are (a) did the horse cover extra ground ie 3 deep for a major part of the race, or even 2 deep facing the breeze? (b) Was the horse held up for a run? (c) Did the horse have to be ridden upside down. In other words having to lead when it likes to sit back or having to drift back through the field to get get closer to the rail when it likes to be on the pace.

In saying this, the occasional, and very rare brilliant jockey can make the best of any barrier.

Cheers

Dave

__________________
When I want to understand what is happening today or try to decide what will happen tomorrow, I look back... Omar Khayyam-1099