title: Does competition improve health care quality?
abstract: OBJECTIVE
  To identify the effect of competition on health maintenance organizations' (HMOs) quality measures.
  
  
  METHODS
  Longitudinal analysis of a 5-year panel of the Healthcare Effectiveness Data and Information Set (HEDIS) and Consumer Assessment of Health Plans Survey(R) (CAHPS) data (calendar years 1998-2002). All plans submitting data to the National Committee for Quality Assurance (NCQA) were included regardless of their decision to allow NCQA to disclose their results publicly.
  
  
  METHODS
  NCQA, Interstudy, the Area Resource File, and the Bureau of Labor Statistics.
  
  
  METHODS
  Fixed-effects models were estimated that relate HMO competition to HMO quality controlling for an unmeasured, time-invariant plan, and market traits. Results are compared with estimates from models reliant on cross-sectional variation.
  
  
  RESULTS
  Estimates suggest that plan quality does not improve with increased levels of HMO competition (as measured by either the Herfindahl index or the number of HMOs). Similarly, increased HMO penetration is generally not associated with improved quality. Cross-sectional models tend to suggest an inverse relationship between competition and quality.
  
  
  CONCLUSIONS
  The strategies that promote competition among HMOs in the current market setting may not lead to improved HMO quality. It is possible that price competition dominates, with purchasers and consumers preferring lower premiums at the expense of improved quality, as measured by HEDIS and CAHPS. It is also possible that the fragmentation associated with competition hinders quality improvement.
authors.affiliation: 504 Ford Building, The Pennsylvania State University, University Park, PA, USA.
authors.forename: Dennis P
authors.initials: DP
authors.lastname: Scanlon
authors.forename: Shailender
authors.initials: S
authors.lastname: Swaminathan
authors.forename: Woolton
authors.initials: W
authors.lastname: Lee
authors.forename: Michael
authors.initials: M
authors.lastname: Chernew
mesh_terms: D000465:Algorithms; D003625:Data Collection; D004465:Economic Competition; D006279:Health Maintenance Organizations / Q000706:statistics & numerical data*; D006801:Humans; D008137:Longitudinal Studies; D008962:Models, Theoretical; D011787:Quality of Health Care / Q000592:standards / Q000706:statistics & numerical data
references.citation: Int J Qual Health Care. 1998 Oct;10(5):421-6
references.pmid: 9828031
references.citation: Health Aff (Millwood). 2003 Mar-Apr;22(2):17-30
references.pmid: 12674405
references.citation: Health Aff (Millwood). 2004 Mar-Apr;23(2):8-21
references.pmid: 15046126
references.citation: Health Aff (Millwood). 2001 Mar-Apr;20(2):274-86
references.pmid: 11260954
references.citation: Health Serv Res. 2001 Apr;36(1 Pt 2):223-51
references.pmid: 11327175
references.citation: Health Aff (Millwood). 1993;12 Suppl:24-48
references.pmid: 8477935
references.citation: Health Aff (Millwood). 2004 Mar-Apr;23(2):25-7
references.pmid: 15046128
references.citation: Health Aff (Millwood). 2001 Mar-Apr;20(2):167-74
references.pmid: 11260940
references.citation: Health Serv Res. 2001 Jul;36(3):619-41
references.pmid: 11482592
references.citation: Health Aff (Millwood). 2005 Sep-Oct;24(5):1302-10
references.pmid: 16162577
references.citation: J Health Econ. 1995 May;14(1):81-105
references.pmid: 10143491
references.citation: Milbank Q. 1998;76(4):737-43
references.pmid: 9879310
references.citation: Med Care. 2005 Apr;43(4):338-46
references.pmid: 15778637
references.citation: Health Aff (Millwood). 2004 Nov-Dec;23(6):11-24
references.pmid: 15584099
references.citation: Health Serv Res. 1998 Dec;33(5 Pt 2):1403-19
references.pmid: 9865226
references.citation: Health Care Financ Rev. 2002 Fall;24(1):83-94
references.pmid: 12545600
references.citation: Inquiry. 2000 Summer;37(2):146-61
references.pmid: 10985109
references.citation: Health Care Financ Rev. 1996 Spring;17(3):171-89
references.pmid: 10158729
references.citation: Med Care. 2000 Oct;38(10):981-92
references.pmid: 11021671
references.citation: Health Aff (Millwood). 1997 Nov-Dec;16(6):75-84
references.pmid: 9444810
references.citation: Med Care Res Rev. 2006 Dec;63(6 Suppl):56S-89S
references.pmid: 17099130
references.citation: J Health Econ. 1996 Dec;15(6):657-84
references.pmid: 10165263
references.citation: N Engl J Med. 2003 Jun 26;348(26):2635-45
references.pmid: 12826639
references.citation: Med Care Res Rev. 2006 Dec;63(6 Suppl):37S-55S
references.pmid: 17099129
references.citation: JAMA. 1999 Jul 14;282(2):159-63
references.pmid: 10411197
references.citation: Health Serv Res. 2001 Apr;36(1 Pt 2):191-221
references.pmid: 11327174
references.citation: J Health Econ. 1990 Sep;9(2):207-22
references.pmid: 10107502