Secretary Arne Duncan used his speech before the National Alliance for Public Charter Schools to spotlight the “bottom 5%” of America’s public schools. Numbering about 5,000, Duncan urged the charter school community to consider taking on some of these schools and turn them around. He was clear that not every charter school operator is up to this challenge, naming a few multiple-site groups like KIPP and Green Dot as possible candidates.

Wrong audience. Bad idea.

If my analysis of New Jersey’s worst-performing schools is any guide, then Secretary Duncan’s plea should be ignored. Expecting charter schools to suddenly operate as turn-around specialists in the nation’s toughest schools is akin to asking the school nurse to perform a liver transplant.

To define the “bottom 5%,” I used the mean scale scores from the 2008 state assessment of 3rd grade language arts. The mean scale score provides a precise number for each of 781 NJ schools in which the 3rd grade test was given. I selected the 39 schools with lowest scale scores for review. Not surprisingly, most of them were near the bottom on the same test in 2004. The 3rd grade literacy test is the threshold test, since kids who do not read at grade level by then have only a 14% chance of ever reading at level. An elementary school that does not teach its students to read and write well is not meeting its primary responsibility.

Here are the findings that prompt my conclusion that little in the experience of charter school innovators prepares them for operating a public school, even if in the same neighborhood.

The one shared characteristic of district and charter school students is their poverty. In fact, charter school students in the five largest NJ cities are slightly more likely to be eligible for free or reduced lunch (73.8% to 66.8%) than district students.

Secretary Duncan’s appeal ignores the central role that is frequently played by the district central office in the performance of individual schools. Of the 39 5% NJ schools, 31 are in Camden (10), Newark (8), Trenton (5), Paterson and Jersey City (4 each). Four are charter schools. Equally poverty-stricken districts like Elizabeth and Union City, not only have no charter schools, but their students regularly perform close to the state average on literacy assessments. These successful districts rely, not on searching out the hero principals Secretary Duncan invokes, but by working closely with teachers and principals to improve classroom pedagogy. And, they emphasize the connection between high-quality preschool and the primary grades with an intensive focus on early literacy.

The persistence and spirit of enterprise required to open and operate a high-performing charter school are to be admired and replicated as often as possible. Secretary Duncan is right to hail the achievements of effective charter schools. However, the experience of attracting students from families seeking better educational opportunities, whose children are free of serious impairments, and who command the English language is entirely different from turning around a failing school in the poorest neighborhoods in the nation. Secretary Duncan did not under-estimate the difficulty of the objective, only the experience and capacity of charter schools to meet the test.