This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance levels--basic and above, proficient and above, and advanced; (2) Background information about limitations of the state's test data and characteristics of the state's testing system, including major changes in its testing system; (3) Figures and tables with the percentages of students scoring at the proficient level and above for all years with comparable data since 1999 and for all grades tested under the No Child Left Behind Act; (4) Figures and tables with percentages of students performing at three achievement levels--basic, proficient, and advanced--for all years with comparable data and for grades 4, 8, and 10 (or adjacent grades, in the case of states that lack comparable trend data for these default grades); (5) Figures and tables with mean scale scores, standard deviations, and effect sizes for all years with comparable data and for the three grades analyzed in this study; and (6) Figures and tables with mean scale scores, standard deviations, and effect sizes for all years with comparable data and for the three grades analyzed in this study. Michigan has made a number of changes to its testing program in recent years. As a result, only three years of comparable data (2006-2008) are available for elementary and middle school reading, the minimum span needed to identify a trend. Only two years of comparable data are available for high school reading and math, too short of a period to determine a trend. In general, Michigan students have made gains at the basic, proficient, and advanced levels. The exception was in elementary reading, where the percentage of students at the basic level and above declined slightly. A notable percentage of students have reached the advanced level in math. Specific results include: (1) Between 2006 and 2008, the percentage of students scoring at the basic level and above in reading decreased slightly at the elementary grade analyzed but showed a moderate-to-large increase at the middle school level; in math, there were moderate-to-large gains in the percentage basic and above at both of these grade levels; (2) In reading, the percentage of students performing at or above the proficient level increased slightly at the elementary level and rose to a moderate-to-large extent at the middle school level; in math, there were moderate-to-large gains in the percentage proficient at both the elementary and middle grades analyzed; and (3) The percentage of students reaching the advanced level grew at a moderate-to-large rate in both reading and math at the elementary and middle grades analyzed; in math, a notable 41% of students in both of these grades reached the advanced level in 2008. (Contains 6 figures and 6 tables.) [For "State Test Score Trends through 2007-08, Part I: Is the Emphasis on 'Proficiency' Shortchanging Higher- and Lower-Achieving Students?," see ED506121. For "State Test Score Trends through 2007-08. Part II: Is There a Plateau Effect in Test Scores?," see ED506122.]