Moving past a disastrous period that led to a loss on paper of more than $900 million — possibly freeing him from federal income taxes for years — Mr. Trump became a one-man factory of big ideas, churning out a continual stream of projects and promises. Together, they fed the image of Mr. Trump as an American Midas, the foundation of his argument for why he would make a great president.

To see whether the results of these ventures came close to their high-energy billing, The New York Times analyzed scores of Trump business announcements starting a decade ago, including those posted on the Trump Organization’s website and those that have been deleted but live on in web archives. The Times also combed through news reports, his personal financial disclosures and court records; interviewed partners; and interviewed Mr. Trump himself.

Of the roughly 60 endeavors started or promoted by Mr. Trump during the period analyzed, The Times found few that went off without a hitch. One-third of them never got off the ground or soon petered out. Another third delivered a measure of what was promised — buildings were built, courses taught, a product introduced — but they also encountered substantial problems, like lawsuits, government investigations, partnership woes or market downturns.

The remaining third, while sometimes encountering strife, generally met expectations — notably the television show “The Apprentice” and the purchases of numerous golf courses, including properties near Philadelphia and in the Hudson Valley.

In interviews, Mr. Trump disputed some of the characterizations, saying that, among other things, some projects that might appear to be failures were successes, for him at least, because he often made his money upfront, through fees for the use of the Trump name. The bottom line of all the hits and misses, however, is impossible to determine because Mr. Trump, the Republican presidential nominee, has not released any tax returns.