(Smart Money) — For all the hype about a few standout schools, charter schools in general aren’t producing better results than traditional public schools. A national study by the Center for Research on Education Outcomes at Stanford found that while 17% of charter schools produced better results than neighborhood public schools, 37% were significantly worse, and the rest were no different. (Not that public schools are perfect, as many parents know. See our earlier story, “10 Things Your School District Won’t Tell You,” for more.) A host of other studies on charter school outcomes have come up with sometimes contradictory results. As with traditional public schools, there are great charters – and some that aren’t so great. “There’s a lot of variation within charter schools,” points out Katrina Bulkley, an associate professor of education at Montclair State University who studies issues related to school governance. “In fairness to organizations that are running high-performing schools, many of them are very frustrated with the range of quality, because they feel that it taints charter schools as a whole,” Bulkley says.