Leaders of the Knowledge Is Power Program (KIPP) charter schools are optimistic that they can reach a long-term agreement with the Baltimore (Maryland) Teachers Union in a nationally watched dispute over teacher pay for an extended school day, reducing the likelihood that the charter network will carry out its threat to close its two schools in that city. The union has indicated its willingness to negotiate a 10-year agreement that meets KIPP's needs. If such a deal became final, the KIPP organization would stop trying to push through the Maryland legislature a bill giving it flexibility to amend an existing collective bargaining agreement as long as 80 percent of teachers in a school agreed to it. At issue is a desire by KIPP not to pay teachers the full hourly rate specified in union contracts for working beyond the regular school day. Longer school days, and even some Saturday classes, are key to the teaching philosophy of the national KIPP network, which now includes 99 public schools in 20 states, and it's also integral to several other charter school models across the country. The practice has raised questions over the years about whether those schools could sustain their programs without risking teacher burnout. The KIPP school day in Baltimore is 9 1/2 hours, or one-third longer than the contractual school day. KIPP, however, negotiated a one-year deal with the Baltimore Teachers Union to pay teachers only 20.5 percent more for the longer school day. The charter operator will not stay in Baltimore unless it can seal that same deal, or a similar one. KIPP schools have the longest school day of any charter school in the city, possibly explaining why the negotiations between KIPP and the union have been more problematic than between other charters and the union. Charter schools in the city address the extra-hours issue through one of three arrangements: (1) they provide an extended school day through after-school programs that are optional for both teachers and students; (2) they offer an extended day that is required for students but not teachers and contract for overtime only with those teachers who step forward; or (3) they require an extra-long day for both students and teachers. KIPP schools fall into that last category.