Funnily enough odds makers are human, meaning they could and often do get it wrong. In fact, if we take statistics into account then we see basically that 1/3 of favorites win. This means 2/3rds of the time they get it wrong.
Of course this is debatable but generally speaking the gist of the matter is that if it was so plain and simple everyone would be cashing out most of the time. Yes, a few individuals from time to time have beaten the books - some with inside info and some by having a better understanding of the art of handicapping and some with constant study time. But, often the inside info goes wrong and the best handicapped horse gets beaten. Also, the best studier can not account for luck in running and also ends up with useless paper exchange for hard cash. But, by and large, the horse that looks a "good thing" on the surface, after an in-depth study has been done, we find it's a case of all that glitters is not gold.
The official handicappers also get the merit rating of horse wrong and sometimes a horse is saddled with a rating above its ability. Therefore, the conditions of the race must be clearly understood by the horse player or his cash turns to useless paper.
Follow this link below to get the official handicapping guidelines.