The Melbourne Cup favourite has won the race a minority of times, with historical figures showing that just over one-quarter of favourites have won in the long run. Recent histories suggest the trend is that favourites win less often than not, and many winners come from mid-to-longer odds rather than the shortest-priced runners. If you’re aiming to judge the likelihood for a given year, you’ll want to compare the current year's favourite against factors like barrier draw, form, weight, and track conditions, as these tend to influence outcomes more than pure odds alone. Key points to consider

• Historical win rate of favourites: roughly in the low to mid-20s percentage over the modern era, meaning about 1 in 4 chances historically. This is not a guaranteed predictor for any single year, but it provides context for expected value calculations.
• Notable recent tendencies: the last couple of Melbourne Cups have seen winners coming from outside the absolute shortest quotes, highlighting the value in looking beyond just the top-priced favourite.
• Additional decision factors: barrier position, the horse’s current form and fitness, distance handling, track condition on race day, and the jockey/trainer combinations.

If you’d like, specify the year or current field you’re looking at, and the exact favourite’s name, and provide any odds or form notes you have. I can tailor a concise, data-driven assessment of the favourite’s chances for that specific race.