Information for Data Submitters: Acute Hospital Case Mix Data

Report Resources

Submission Deadlines

Begin & End Dates


Oct. 1st - Dec. 31st
March 16th
Jan. 1st- March 31st
June 14th
April 1st - June 30th
Sept. 13th
July 1st - Sept. 30th
Dec. 14th

Please Note: Preliminary quarterly Hospital Inpatient Discharge, Emergency Department, and Outpatient Observations submissions are due on the last day of the month following the close of the quarter.

For more information, see Administrative Bulletin 21-04 and Administrative Bulletin 22-01.


CHIA collects hospital data on patient demographics, diagnoses and procedures, physicians, and charges for each inpatient discharge, outpatient observation stay, and emergency department visit in Massachusetts. Hospitals submit data in accordance with the requirements of the Data Submission Specification Manuals, which set forth the file format, record specifications, data elements, definitions, code tables, and edit specifications for each database. These manuals can be found in the blue box on the right of this page. Hospitals submit inpatient, outpatient observation, and outpatient emergency department data quarterly.


Filing Application

Acute hospitals submit their Case Mix data through a User interface.

Completed agreement forms need to be emailed to For more information about CHIA’s web transaction interfaces (e.g. CHIA-INET, CHIA Submissions), see CHIA-INET and CHIA Submissions Questions & Answers.

CHIA occasionally hosts Case Mix Technical Assistance Group (“TAG”) webinars where hospitals may ask questions about data submission. On the right of this page, you can find presentations in connection with the most recent TAG webinars.



Please email Cathy Houston or call (617) 701-8100 regarding either Case Mix Hospital or Behavioral Health Facility submissions.