EXPLAINER: Why are Chicago schools, teachers union fighting?

CHICAGO (AP) — Chicago has scrapped classes for days in a confusing standoff with the teachers' union over COVID-19 safety measures in the nation's third-largest school district.

From remote instruction to testing, both sides have been negotiating nearly a dozen complex points of a safety plan that has cast a shadow over a second week of school. The fight comes as other districts have had to increasingly shift online amid soaring COVID-19 cases.

Here is a closer look at the status of negotiations in Chicago:

REMOTE LEARNING

The issue causing the most chaos in the roughly 350,000-student district is when and how to revert to remote learning.

The Chicago Teachers Union wants the ability to switch to districtwide remote instruction and offered a lower bar for closing individual schools. Their proposed metrics are similar to last year's safety agreement, which expired before the school year began and has since been under negotiation. They want to shut schools citywide for criteria including: Chicago's COVID-19 test positivity rate increases for seven consecutive days and the rate for each of the days is at least 15% higher than the rate the previous week.

School leaders flat out oppose any districtwide return online, so much that they have opted to cancel classes rather than allow it temporarily as the union has argued is necessary amid the spike. Chicago Public Schools leaders say the pandemic is different now compared to a year ago with availability of vaccines and roughly 91% of staff vaccinated. School officials also say remote learning is harmful for academics and children's wellbeing, and encourages racial inequity.

Two days after students returned from winter break, the union voted to return to remote instruction on its own and most union members stayed out of...