Glitches in Los Angeles Payroll System Spark Furor

Thousands of Los Angeles teachers have not been paid properly for months because of errors in a corporate-style payroll system that was introduced in January as part of a sweeping, $95 million computer modernization.

The Los Angeles Unified School District acknowledges that the payroll system’s rollout was rushed and tainted by numerous programming glitches and insufficient training of school-based pay officials.

Yet the district teachers’ union has not been satisfied with such explanations. It sued the district this spring , even before a massive failure of the system on June 5—a day the district now calls “Black Tuesday”—when roughly 28,000 employees were overpaid and 4,500 received less...