"Easily the best episode of the show since the third season and maybe even since that magical stretch around the midpoint of season two. It's an episode that contains ample amounts of both the laughs and the deeply felt emotional core that make this show work so well at its best. [It's] also wildly, wildly funny."
-The A.V. Club
"What a thoroughly satisfying and deeply funny episode of Community that was. The dialogue and pacing crackled."
-Vulture (New York magazine)
"An all-time classic. This half-hour...should be able to stand with the rest of the upper echelon episodes of Harmon's first three seasons."
"Remarkably tender, uncommonly precise."
"Just a terrific episode."
"Well, that was excellent. Like really, really excellent, the kind of excellence that can only be measured by comparing it to other really, really excellent episodes of Community. The 'best since...' game is a tricky one to play...but 'Cooperative Polygraphy' lived up to the critical hype: it may have been the show's best episode since [the Emmy Award-nominated] 'Remedial Chaos Theory.'"
"One heck of a great episode of Community, and the best of the show's revitalized fifth season to date. Community at its finest...a shoestring-budget masterpiece. Easily a Top 10 episode of Community."