The trouble is that business journalists know as much about business as sportswriters know about sports and political journalists know about politics. Fortunately, students of politics have it easier than students of sports or business because politicians have to explain themselves to get what they want. If you want to understand Trump, the first step is to look to his own words, the second step to look to words of the politicians who are his allies, and the third to look to the words of the politicians who are his rivals and enemies.
As for prediction markets, the efficient markets hypothesis says they integrate publicly available knowledge. That does not mean that they are accurate, just that anything more accurate is going to cost you.
The odds on a Republican
Should you trust me? I have not, so far, put any money down on Trump at Iowa. But the people who bought Trump in the Republican convention market at IEM are doing well so far, as today's graph shows.
Are the prediction market odds a good guide to Trump's actual chances? Were they a good guide to his chances the day after the Iowa caucuses? All we can say with any degree of assurance is that they are a better guide than any other you can get for free.
Trusting me isn't free.