Overlap in HMO physician networks

Health Affairs

Volumn 23, Issue 2, 2004, Pages 91-101

  Chernew, Michael E ^a   Wodchis, Walter P ^b   Scanlon, Dennis P ^c   McLaughlin, Catherine G ^d  

^a UNIVERSITY OF MICHIGAN   (United States)

^b INSTITUTE FOR CLINICAL EVALUATIVE SCIENCES   (Canada)

^c PENNSYLVANIA STATE UNIVERSITY   (United States)

^d NONE

Author keywords

[No Author keywords available]

Indexed keywords

ARTICLE; HEALTH CARE; HEALTH CARE ACCESS; HEALTH CARE COST; HEALTH MAINTENANCE ORGANIZATION; HUMAN; MANAGED CARE; PHYSICIAN;

EID: 1842729535     PISSN: 02782715     EISSN: None     Source Type: Journal    
DOI: 10.1377/hlthaff.23.2.91     Document Type: Article

References (19)

1. J. White, "Choice, Trust, and Two Models of Quality," Journal of Health Politics, Policy and Law 24, no. 5 (1999): 993-999.
2. For evidence of the spread of these laws, see R.L. Ohsfeldt et al., "The Spread of State Any Willing Provider Laws," Health Services Research 33, no. 5, Part 2 (1998): 1537-1562; and J.A. Marsteller et al., "The Resurgence of Selective Contracting Restrictions," Journal of Health Politics, Policy and Law 22, no. 5 (1997): 1133-1189. Analysis of their effects can be found in C.A. Ambrose and J.M. Ambrose, "Any-Willing- Provider Laws: Their Financial Effect on HMOs," Journal of Health Politics, Policy and Law 27, no. 6 (2002): 927-945; and M.G. Vita, "Regulatory Restrictions on Selective Contracting: An Empirical Analysis of 'Any Willing Provider' Regulations," Journal of Health Economics 20, no. 6 (2001): 955-966.
3. For evidence of the spread of these laws, see R.L. Ohsfeldt et al., "The Spread of State Any Willing Provider Laws," Health Services Research 33, no. 5, Part 2 (1998): 1537-1562; and J.A. Marsteller et al., "The Resurgence of Selective Contracting Restrictions," Journal of Health Politics, Policy and Law 22, no. 5 (1997): 1133-1189. Analysis of their effects can be found in C.A. Ambrose and J.M. Ambrose, "Any-Willing- Provider Laws: Their Financial Effect on HMOs," Journal of Health Politics, Policy and Law 27, no. 6 (2002): 927-945; and M.G. Vita, "Regulatory Restrictions on Selective Contracting: An Empirical Analysis of 'Any Willing Provider' Regulations," Journal of Health Economics 20, no. 6 (2001): 955-966.
4. For evidence of the spread of these laws, see R.L. Ohsfeldt et al., "The Spread of State Any Willing Provider Laws," Health Services Research 33, no. 5, Part 2 (1998): 1537-1562; and J.A. Marsteller et al., "The Resurgence of Selective Contracting Restrictions," Journal of Health Politics, Policy and Law 22, no. 5 (1997): 1133-1189. Analysis of their effects can be found in C.A. Ambrose and J.M. Ambrose, "Any-Willing- Provider Laws: Their Financial Effect on HMOs," Journal of Health Politics, Policy and Law 27, no. 6 (2002): 927-945; and M.G. Vita, "Regulatory Restrictions on Selective Contracting: An Empirical Analysis of 'Any Willing Provider' Regulations," Journal of Health Economics 20, no. 6 (2001): 955-966.
5. For evidence of the spread of these laws, see R.L. Ohsfeldt et al., "The Spread of State Any Willing Provider Laws," Health Services Research 33, no. 5, Part 2 (1998): 1537-1562; and J.A. Marsteller et al., "The Resurgence of Selective Contracting Restrictions," Journal of Health Politics, Policy and Law 22, no. 5 (1997): 1133-1189. Analysis of their effects can be found in C.A. Ambrose and J.M. Ambrose, "Any-Willing- Provider Laws: Their Financial Effect on HMOs," Journal of Health Politics, Policy and Law 27, no. 6 (2002): 927-945; and M.G. Vita, "Regulatory Restrictions on Selective Contracting: An Empirical Analysis of 'Any Willing Provider' Regulations," Journal of Health Economics 20, no. 6 (2001): 955-966.
6. L.B. Benko, "Willing and Able: Supreme Court Ruling Forces HMOs to Open Networks to Any Willing Provider; Some Say It May Wound Managed-Care Industry," Modern Healthcare 33, no. 14 (2003): 6-7.
7. This effect is related to the literature on job lock, which examines the extent to which the lack of availability of coverage in some jobs deters people from switching jobs. See B.C. Madrian, "Employment Based Health Insurance and Job Mobility: Is There Evidence of Job Lock?" Quarterly Journal of Economics 109, no. 1 (1994): 27-54.
8. N.D. Beaulieu, "Externalities in Overlapping Supplier Networks" (Unpublished manuscript, Harvard University, 2002).
9. Ibid.; R.A. Berenson, "Beyond Competition," Health Affairs (Mar/Apr 1997): 171-180; and A.E. Roussel et al., "Primary Care Physicians' Participation in Managed Care Networks," Journal of Ambulatory Care Management 22, no. 2 (1999): 27-40.
10. Ibid.; R.A. Berenson, "Beyond Competition," Health Affairs (Mar/Apr 1997): 171-180; and A.E. Roussel et al., "Primary Care Physicians' Participation in Managed Care Networks," Journal of Ambulatory Care Management 22, no. 2 (1999): 27-40.
11. Ibid.; R.A. Berenson, "Beyond Competition," Health Affairs (Mar/Apr 1997): 171-180; and A.E. Roussel et al., "Primary Care Physicians' Participation in Managed Care Networks," Journal of Ambulatory Care Management 22, no. 2 (1999): 27-40.
12. D.A. Draper et al., "The Changing Face of Managed Care," Health Affairs (Jan/Feb 2002): 11-23.
13. See D.P. Scanlon et al., "Options for Assessing PPO Quality: Accreditation and Profiling as Accountability Strategies," Medical Care Research and Review 58, Suppl. 1 (2001): 70-100; and D.G. Smith, "The Effects of Preferred Provider Organizations on Health Care Use and Costs," Inquiry 34, no. 4 (1997-1998): 278-287.
14. See D.P. Scanlon et al., "Options for Assessing PPO Quality: Accreditation and Profiling as Accountability Strategies," Medical Care Research and Review 58, Suppl. 1 (2001): 70-100; and D.G. Smith, "The Effects of Preferred Provider Organizations on Health Care Use and Costs," Inquiry 34, no. 4 (1997-1998): 278-287.
15. ProAct Health Pages collects and merges these lists to generate a comprehensive database of plan-physician combinations for employers who want an easy way for their employees to search for affiliated physicians or check if their physician is in any given plan. More information can be found at www.proactcorp .com. For additional detail, see ProAct, "Health Pages," thehealthpages.com/articles/about.html (3 December 2003), which includes the following text: "Health Pages also incorporates the provider directories of over 300 managed care plans into our physician superdirectory, which allows consumers to determine what plans each doctor is affiliated with."
16. We made this exclusion because we were concerned that plans with fewer than ten physicians in a market were not really serving that market and that the data might be erroneous. The results are qualitatively similar using no exclusion criteria or strengthening it to require plans have at least a 5 percent share of the HMO market in the MSA.
17. It should be noted that hospital-based physicians (radiologists, anesthesiologists, pathologists, and hospitalists) often do not appear on health plan provider lists. Our measure of overlap is thus best interpreted as a measure of overlap among community-based physicians.
18. The share of physicians in Plan A that also serve Plan B will not, in general, be the same as the share of physicians in Plan B that serve Plan A. For example, plans with few physicians may have complete overlap with a larger plan, but the larger plan may have many physicians not offered by the smaller plan.
19. We were concerned that this might be an underestimate of the effective amount of overlap if not all plans served all areas of the MSA. We therefore recomputed the unweighted overlap measure using the county as the definition of market and found that the increase in overlap was not substantial, rising four percentage points to 61 percent.