08/18/2009, John Rudoy: The Chicago Public School System recently announced it will be putting over 100 schools on the year-round calendar. There are already about 250 Chicago schools that have been put on some form of year-round calendar in the last few years. Some media reports have noted that such year-round schools show worse performance on standardized test scores, but this graph demonstrates that such claims are misleading. Year-round schools do show worse test scores, but those schools were worse even before they were switched to the year round calendar (between 2005 and 2009), and have actually shown more improvement over time than Regular-calendar schools.