What is sort priority in betfair data

[favetelinguis]

Im just trying to understand all the language used in horse racing. For example in one of Peters youtube videos he says that there is a strong correlation between the price movements of the favorite and the second favorite. I dont understand what is meant with favorite? That is does this correlation change at every time instance given best back bet at that moment or is this someting that is fixed even before the market starts given some news in a paper leading up to the race? Lets say to want to sort the ladders so I at every time instance have the favorite and the second favorite (between wich Peter claims there are a strong correlation) as my 2 most left ladders, what would be the best data to base this sorting on? Would it be sort priority in the betfair API data, the best back offer, LTP or some other data?

[ShaunWhite]

I dont understand what is meant with favorite?

The horse with the shortest back odds, 2nd Favourite = 2nd shortest etc
When two have the same odds they are called Joint Favourites.

Lets say to want to sort the ladders so I at every time instance have the favorite and the second favorite (between wich Peter claims there are a strong correlation) as my 2 most left ladders

Sort by the current back price. BetAngel has an icon to do this, the "123" button at the top of the ladder page.