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Minimum Data Set (Long-Term Care)


  • Owner / manager
  • Study and sample characteristics
  • Major foci
  • Special supplements and resources
  • Links to other datasets
  • Papers published
  • Dataset accessibility and cost
  • Help desk

    Key web links    

    Home page

    Data elements

    Description of data elements in the MDS can be found in Chapter 3 of the RAI User’s Manual, available through the following link.  It is a very long file.  

    Dataset Summary

    The MDS system collects data on the physical, psychological, and psychosocial functioning of all residents of long-term facilities certified by Medicare or Medicaid.  Each patient in such facilities (regardless of payor type) undergoes serial MDS assessments at admission, quarterly and annually, and upon a major change in status.  MDS data is routinely used for monitoring of nursing home quality and performance, but has also been widely employed for research, with data files from 1998 through the present.  Data from MDS can be linked with other Medicare and Medicaid files.  Data is available via an application process; fees vary depending on the scope of the data request.
    Expert comments
     The MDS can be linked to several datasets provided by the Centers for Medicare and Medicaid Services (CMS). This is the real strength of this dataset. If linked, analyses can be conducted to include both facility level (long term care facility) and individual patient level factors. In addition, MDS data can be linked to National Death Index data in order to study survival as an outcome.
    As the MDS is collected for clinical purposes, one should be aware of its inter-rater reliability when using the data for research purposes. Please note that the inter-rater reliability varies greatly for each item on the MDS, although most are high (>0.75). Below are several references with more details about the reliability of MDS items.
    Reliability estimates for the Minimum Data Set for nursing home resident assessment and care screening (MDS).
     Hawes C, Morris JN, Phillips CD, Mor V, Fries BE, Nonemaker S.
     Gerontologist. 1995 Apr;35(2):172-8.
    Inter-rater reliability of nursing home quality indicators in the U.S.
     Mor V, Angelelli J, Jones R, Roy J, Moore T, Morris J.
     BMC Health Serv Res. 2003 Nov 4;3(1):20.  

    Dataset Details


    Dataset owner / manager 

    Centers for Medicare and Medicaid Services (CMS); support is provided through the ResDAC program at the University of Minnesota

    Study and sample characteristics  

    Complete longitudinal sample of all residents of long-term care facilities certificated to participate in Medicare or Medicaid.  Each patient receives MDS assessment on admission, quarterly and annually, and upon major change in status.  Data is available from 1998 through the present. 

    Major foci 

    MDS includes data on a variety of topics, summarized below.  Other, specialized information not listed below is also available.  Data collected varies by the type of assessment (e.g. admission, quarterly, annually, change of status).
    •    Demographics
     •    Daily activities and function
     •    Communication, hearing, vision
     •    Mood and behavior
     •    Psychosocial well-being
     •    Physical functioning and structural problems
     •    Continence
     •    Disease diagnoses and health conditions
     •    Oral, nutritional, and dental status
     •    Skin condition
     •    Activity patterns
     •    Special treatments and procedures
     •    Discharge potential and overall status

     •    Therapies (e.g., physical therapy)
     •    Discharge information
     •    Medications

    The questionnaire is available at

    A comprehensive list and explanation of data collected is in Chapter 3 of the RAI User’s Manual, available through the following link.  It is a very long file. 
    Links to other datasets   
    MDS data can be linked with other CMS datasets (such as Medicare and Medicaid data) using unique patient identifiers.
    Papers published    

     Click here for a PubMed search for articles using this dataset.

    Potentially modifiable resident characteristics that are associated with physical or verbal aggression among nursing home residents with dementia.
     Leonard R, Tinetti ME, Allore HG, Drickamer MA.
     Arch Intern Med. 2006 Jun 26;166(12):1295-300.
    Effect of educational level and minority status on nursing home choice after hospital discharge.
     Angelelli J, Grabowski DC, Mor V.
     Am J Public Health. 2006 Jul;96(7):1249-53.
    Venous thromboembolism among elderly patients treated with atypical and conventional antipsychotic agents.
     Liperoti R, Pedone C, Lapane KL, Mor V, Bernabei R, Gambassi G.
     Arch Intern Med. 2005 Dec 12-26;165(22):2677-82.
    Estimating prognosis for nursing home residents with advanced dementia.
     Mitchell SL, Kiely DK, Hamel MB, Park PS, Morris JN, Fries BE.
     JAMA. 2004 Jun 9;291(22):2734-40.
    Resident-to-resident violent incidents in nursing homes.
     Shinoda-Tagawa T, Leonard R, Pontikas J, McDonough JE, Allen D, Dreyer PI.
     JAMA. 2004 Feb 4;291(5):591-8. 
    Dataset accessibility and cost   
    For identifiable data files you must compete and submit a data request packet to ResDAC.  Fees for data processing vary by request, with the most complex requests costing up to $5,000 per year of national data, although other requests may cost substantially less.
    According to the ResDAC website, MDS data are also available as limited data set files, although in practice they may not be readily available.  Contact the ResDAC help desk for up-to-date information.

    Help Desk  
    Research Data Assistance Center (ResDAC)