PHILADELPHIA (CBS) — How can Philadelphia attract — and keep — qualified teachers for its public schools? City Council looked into that question at a hearing on Monday.

It’s been four years since Philadelphia teachers had a raise. Philadelphia Federation of Teachers president Jerry Jordan says that’s making it hard to attract talent.

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“The lack of a contract is a sign of instability that discourages potential educators from coming to Philadelphia,” Jordan said.

The district’s chief financial officer, Uri Monson, told Council’s education committee that a “yawning gap” remains between the two sides.

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“The district has limited resources, and is unwilling to enter into an agreement which would lead to resources being cut from schools and classrooms, and would require a return to layoffs of our teachers, counselors and nurses,” Monson said.

The district told Council’s education committee there have been 300 vacancies since the start of the school year, with about 100 still unfilled.

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Monson says the district offered teachers a $1,500 bonus to teachers who agreed to retire in June, instead of mid-year, as a way to reduce vacancies, but the union rejected that.