March 23, 2005   Dear Manhattan Beach Parents,   When the 818 Academic Performance Index (API) score was announced last week for Mira Costa High School, no statewide rank or similar schools rank data was listed.  Instead, in place of that data was an “I” indicating that the school had some invalid data and as a result, the California Department of Education (CDE) could not calculate a valid statewide or similar schools rank.   The problem is not with the test data, which is accurate, but with a computer glitch, which blanked out student enrollment dates.  The district and the CDE are addressing the issue at this time.  When corrected, the data will be available.     Thank you for your support,     Gwen E. Gross, Ph.D. Superintendent of Schools