Three-quarters of Denver classroom teachers were absent on the first day of a three-day strike earlier this month, according to attendance numbers obtained through an open records request.

That’s higher than the 56 percent teacher absentee rate the district reported on the strike’s first day. The figure was disputed at the time by the teachers union, which argued that its own attendance tally from the picket lines showed more support for the strike than the district was reporting. The numbers are significant because they are one measure of how many educators backed the union demands.

A district spokesperson explained that the district’s day-of count was based on information from school principals, some of whom may have been delayed in reporting teacher absences.

At the heart of Denver’s teacher strike was a dispute over how — and how much — the district’s educators are paid. By the time teachers took to the picket lines on Feb. 11, Denver Public Schools and the Denver Classroom Teachers Association had been negotiating for 15 months without reaching agreement on how to revamp the district’s complex teacher pay system.

Strike participation varied widely at schools across the district, the numbers show. At one extreme were three schools — Lena Archuleta Elementary, Florence Crittenton High School, and Respect Academy — where no teachers showed up the first day of the strike.

One issue the union and the district were debating was whether teachers at 30 “highest-priority” schools should continue to get bonuses for returning year-over-year or whether the money should go into raising salaries for all teachers. The final contract ultimately kept those bonuses, which were a top district priority.

Participation in the strike was low at some schools that get the bonuses but high at others. It ranged from 90 percent at North High School to just 7 percent at Cheltenham Elementary School, which had among the lowest participation in the district.

Look up your school in our searchable table below. It shows the percentage of teachers absent at each district-run school on the first day of the strike.

Districtwide, teacher participation in the strike decreased slightly from the first day (75 percent) to the second (74 percent) to the third (73 percent). The district’s numbers only include teachers. They do not include “specialized service providers,” such as nurses and counselors, who are also part of the Denver Classroom Teachers Association and participated in the strike.

Our searchable table also shows student absences. Unlike teacher absences, which decreased as the strike continued, the total percentage of students absent at all district-run schools increased from 26 percent on the first day of the strike to 30 percent on the third day.

Student attendance also varied widely from school to school.

On the second day of the strike, the district and the union returned to the bargaining table. They met again on the third day, hashing out their differences for 20 straight hours.

The two sides announced a tentative agreement just before dawn the following morning, Feb. 14, and the union called off the strike. Because of the timing, not all teachers returned to the classroom that day. The district’s numbers show 31 percent of teachers were still absent. By Feb. 15, which was a Friday, the absentee percentage had fallen to 15 percent.

Note: After the story was published, we heard concerns about the data from teachers at schools showing no teacher absences. Teachers at those schools, including Denver Online High School and EXCEL Academy, said teachers there did go on strike. We reached out to the district, which explained that “the data only represents what was reported, and in those two cases, may not be an accurate picture of teachers’ participation in the strike.” We’ve removed the reference to those schools from the story.