I'm starting to see that analysis, from Topline Translator, bouncing around the opinionsphere. The basis is a Democracy Corps poll that "shows support for the Ryan budget at 52-37% — a +15% margin." But that's not quite what it does. Democracy Corps gave voters a paragraph's worth of positive spin about the Ryan plan, to test how Republicans might best describe it.
Our plan saves the country from a future of spending and debt by cutting an additional 5.3 trillion dollars over the next ten years, bringing federal spending down to the historic level of 20 percent as a share of the economy, and bringing deficits down by 2015. Our plan fixes the broken tax code by making it simple, fair and competitive, and eliminates special interest loopholes while lowering everyone's rates to promote growth. Our plan repeals the Obama administration's health care reform law and the Wall Street reform law, which cause uncertainty for job-creating businesses. Our plan strengthens Medicaid over the next decade by providing states greater flexibility to determine what is best for the people who live in their communities. Our plan will save Medicare for future generations by making smart reforms, giving future seniors the choice to purchase private plans or traditional Medicare.
So: 52% of voters approved of that language, with its promise of freedom for job creators, painless spending cuts, and "fair" taxes with no info about the rates or deductions. What DC then did was ask voters if some niggling issues with the plan gave them doubts. "The plan gives those making over a million dollars a year an average tax cut of more than 150,000 dollars, while cutting programs that middle and working class families depend on," said the pollster, in a leading but true statement. Sixty-one percent of voters said that gave them doubts. The rest of the study goes through similar messaging questions, finding that "simpler taxes" work well for the GOP, exploring for weak spots to hit the GOP's candidates.
Short version: No, 52% of voters don't automatically favor the Ryan budget. This gets at the problem Romney faces as he thinks about picking Ryan for VP -- how much do people turn on the Ryan plan when they're told what to hate about it? (Of course, whoever Romney picks as VP, if he's president he's said he'll sign whatever Ryan gives him.)