A poll can generate headlines, as one did this morning with the story that a majority of DCPS parents approve of the school system’s performance for the first time in a decade. But polls are also snapshots capturing a particular moment in time, and they may not fully reflect the reality on the ground.

The six previous Post polls that sampled parent attitudes between 1998 and 2010 show deep swings in sentiment. The last time parent approval hit the 50 percent mark was in February 2000. That rating, up from 36 percent in May 1998, seemed to reflect, as The Post described in its article, a District “awash in optimism about itself and its political leaders,” with large majorities of black and white residents expressing broad approval of Mayor Anthony A. Williams and his efforts to clean up and modernize city government.

Much of the commentary in the year leading up to the survey reflected the kind of cautious optimism that is part of the current conversation. Arlene Ackerman had replaced Gen. Julius Becton as superintendent and was said to be making sweeping changes in hiring and instructional practices. The school system was due to exit its Control Board takeover in mid-2000. Test scores (the old Stanford 9, forerunner of the DC CAS) were going up. A Post editorial praised the “slow but continuing progress.”

In August 1999, Ackerman staged a rally at the MCI Center to mark the beginning of the school year, an event dubbed “Reaching Higher: On the Road to Exemplary Achievement.” Attendance for teachers was mandatory.

But conditions in the schools remained bleak. The city was stunned in October 1999 by the story of Freddy Ramirez, a 9-year-old boy with cerebral palsy, who had to crawl to the toilet at his elementary school because he couldn’t get his wheelchair through the door.

And while Ackerman was publicly proclaiming progress, she was quietly seething. In January 2000, my colleague Valerie Strauss wrote:

“[Ackerman] has spent most of the last 20 months in unending frustration in the District — where dust-ups over money, governance and policy cloud her days, where failures make headlines and successes often go unnoticed, where some parents and policymakers accuse her of taking two steps backward for every one forward.”

Five months later, Ackerman was gone, headed to the superintendency of San Francisco’s schools. Subsequent Post polls showed a drop in parental approval, in May 2002 (48 percent), July 2006 (30 percent) and January 2008 (31 percent). The numbers began to tick back up again in January 2010 (46 percent) under Chancellor Michelle A. Rhee.

Some readers questioned the legitimacy of polling parents about their schools. “What difference does it make how the parents feel about school performance when by almost all objective measures they are not good?” one asked today. “The product turned out by DCPS is substandard even when compared to other U.S. schools. ... Claiming improvement from catastrophic to merely dismal is not really progress.”

Kathy Patterson, a former D.C. Council member (1995-2007) and chair of its education committee, said a public opinion survey may not be the best tool for learning how parents feel about their schools.

“It’s one of these things that’s very difficult to tease out,” she said. “It’s like polling on your member of Congress.” Polls generally show that while people dislike Congress as an institution, they are more approving of their own representative. Patterson said parent focus groups might be more revealing.