Essay: Earnings management in Dutch hospitals

LIST OF ABBREVIATIONS
CEO(s) – Chief Executive Officer(s)
DTC(s) – Diagnosis Treatment Combination(s)
DRG(s) – Diagnosis Related Group(s)
NZa – Dutch Healthcare Authority (in Dutch, Nederlandse Zorgautoriteit)
PPS – Prospective Payment System
DOT – DTCs on their way to transparency (in Dutch, DBCs op weg naar transparantie)
GAAP – Generally Accepted Accounting Principles
‘
LITERATURE REVIEW AND HYPOTHESIS DEVELOPMENT
HISTORY OF DUTCH HOSPITAL FUNDING
In the health care industry, several (hybrid) schemes for hospital funding exist. Every scheme has its own set of advantages, drawbacks and financial incentives for hospital chief executive officers (CEOs). Hospitals, as they are nonprofit organizations, have different organizational, managerial, and financial incentives than for-profit organizations. The most important difference is that, in contrast to for-profit firms, hospitals do not have a profit objective. When they do report positive earnings, they use that surplus to improve healthcare rather than distribute the positive earnings to, for example, shareholders. Due to the fact that hospitals are nonprofit organizations, most people do not view hospitals economic entities that respond to financial incentives, even though prior research shows that there is little distinction between the outputs and behaviors of profit and nonprofit CEOs (Brickley and Van Horn 2002).
Since 1988, hospital care in the Netherlands was funded by means of an external budget. In this model, each hospital received a certain amount, after negotiations with health insurance companies about the height of that amount. The purpose of this model was to relate a hospital earnings to its productivity. Hospitals should be paid an equal amount for performing equal parts. The paid amount consists of a fixed and a variable component. The fixed part consists of property charges (e.g. depreciation), the amount of residents that are assigned to the hospital and the hospital capacity, expressed in the amount of beds and medical specialist FTEs. The variable part is based on hospital admissions, inpatient days, first outpatient visits and day care visits. Since the fixed part counted for almost 50% (in 1992) of hospitals earnings, there were little incentives for hospitals to improve efficiency. Either way, they received money. The external budget did not include all hospital expenditures, some were reimbursed on a retrospective cost basis. Under the retrospective cost-based reimbursement system, hospitals revenue is equal to the reported costs allocated to a patient’s hospital stay. Under this system, there is little incentive to control costs since higher costs result in higher levels of reimbursement.
In 1993 a committee under the leadership of former Prime Minister Barend Biesheuvel, set up by the Ministry of Health, advised a fundamental revision of hospital funding in the Netherlands, based upon the principle of the prospective payment system (PPS). Within this system, reimbursement is based on a pre-determined payment, regardless of the intensity of the actual service. The Dutch government was enthusiastic about the project, since the government supports market competition in an increasing number of industries (e.g. the telecommunications industry). Prior research documents that increased market competition leads to lower prices and higher quality medical and supporting services, which are the core activities of hospitals (Maarse and Bartholom??e 2007; Van de Ven and Schut 2008). The project eventually led to the introduction of a unique new reimbursement system, based on Diagnosis Treatment Combinations (in Dutch Diagnose Behandel Combinaties, or DBCs).
THE DIAGNOSIS TREATMENT COMBINATION PAYMENT SYSTEM
The Diagnosis Treatment Combination (DTC) payment system gives hospitals and health insurance companies the opportunity to negotiate about the price, quality and volume of certain hospital treatments. For patients this is beneficial, since increased market competition leads to better quality, accessibility and costs of healthcare. Furthermore, the system improves the possibilities to compare hospitals’ performance. Hospitals can use this information to improve the efficiency of their operations and to compete with each other on price and quality.
A DTC is defined as the whole of medical and supporting services, that are needed for a patient, stemming from the demand for care for which the patient consults the specialist. The (most appropriate) DTC choice is made after the first consult, by the medical specialist who treats the patient. After the treatment has come to an end, the medical specialist closes the DTC. Thereafter, the DTC must be validated and checked by the hospital so that it can be sent to the health insurance company for reimbursement. The validation and checking process is performed by an internal control procedure in the hospital. Also, an external accountant checks this internal control procedure (at least) annually.
Under the DTC payment system, the hospital revenue for a specific DTC is equal to a predetermined, fixed amount. This amount is either fixed and set by the Dutch Healthcare Authority (NZa) (A-segment, 90% in 2005 but decreased to 30% in 2011) or negotiated with health insurance companies (B-segment, 10% in 2005 but increased to 70% in 2011). The costs of remuneration of specialists (medical services) and hospital resources (supporting services) are both included in the price of a DTC and are invoiced to the health insurance companies as one price.
The hospital keeps or loses the difference between the DRG rate and their actual costs, which encourages hospitals to become more profitable through cost and waste reduction (S??derstr??m 1990). Guterman and Dobson (1986) provide evidence that under PPS, hospitals increase earnings by reducing costs and/or the amount of services provided to patients. Hospitals can also find ways to increase reimbursement, instead of cost reduction. Silverman and Skinner (2004) and Heese and al. (2012) find evidence that hospitals were accused of ‘upcoding’ patient DTCs to increase reimbursement. Since hospitals receive reimbursements for each patient admission, it gives them incentives to admit more patients, as long as the DTC rate is higher than their actual costs.
A major change took place in 2012 with the development of DOT (DTCs on their way to transparency). This method will lead to a full market force since all DTCs are part of the negotiable B-segment. The NZa states that the funding system in the Netherlands is highly improved by the introduction of DOT, since 30.000 DTCs are replaced by 4.400 DOTs (also diagnosis-related groups) which are medically more recognizable. Furthermore, the DTC is selected after the medical and supporting services are provided based on registered activities, instead of estimations beforehand.
EARNINGS MANAGEMENT INCENTIVES
Earnings management is defined by Schipper (1989) as the strategic exercise of managerial discretion in influencing the earnings figure reported to stakeholders. According to Degeorge et al. (1999) executives in the corporate sector both have the incentives as well as the abilities to manage reported earnings.
Hayn (1995) has shown that for-profit companies try to avoid reporting negative earnings. The results in her paper suggest that companies whose earnings are expected to fall just below the break-even point engage in earnings management to create positive earnings. Burgstahler and Dichev (1997) also provide evidence that firms manage reported earnings to avoid reporting negative earnings. They give two possible explanations for the phenomenon. The first is based on the fact that firms with higher earnings face lower costs in transactions with stakeholders (e.g. financing companies) (Cornell and Shapiro 1987). The second is based on the prospect theory (Kahneman and Tversky 1979). The prospect theory postulates that stakeholders evaluate positive and negative earnings using certain heuristics, for example a break-even reference point, therefore firms avoid reporting negative earnings.
A number of studies suggest that financial performance incentives in for-profit companies and the health care industry are similar (e.g. Van Herck 2003). Leone and Van Horn (2005) find three patterns of earnings management that can be distinguished in the health care industry: manage earnings upwards, manage earnings downwards and manage earnings towards just above zero. This three patterns will be discussed below for the Dutch health care industry.
First, hospitals can have financial incentives to manage their reported earnings upwards. According to Eldenburg et al. (2011) hospitals face similar pressures as for-profit companies to increase reported earnings. Leone and Van Horn (2005) suggest that reported earnings serve as a measure of the ability of the hospitals’ CEO to sustain the hospital as a going concern, although positive earnings are not the hospitals’ primary objective. CEO turnover is relatively high in the health care industry and is negatively related to financial performance (Brickly and Van Horn 2002; Ballantine et al. 2008). Reporting negative earnings will increase the likelihood that the hospitals’ CEO will be replaced because negative earnings suggest that the hospitals’ CEO violated the zero profit constraint. Besides the damage to their reputation for CEOs, a lot of Dutch hospitals raise capital by issuing debt since they cannot issue shares. This can be an incentive for hospital CEOs to engage in earnings management. Considering the risk-return theory and Leone and Van Horn (2005), debt holders ask a higher return when risk increases. For hospitals showing positive earnings, it is easier to repay the debt which lowers the risk for debt holders and thus the costs of debt for hospitals.
Second, hospitals can have financial incentives to manage their reported earnings downwards. The explanation of Eldenburg et al. (2011) for this behavior is that health insurance companies will push for price concessions when hospitals report high positive earnings. This, in turn, will decrease the predetermined, fixed amount that the hospital will receive for a specific DTC. Furthermore, hospitals have a social objective instead of a profit objective. High positive earnings put hospitals in a bad light and will lead to more regulatory involvement of the government (Ballantine et al. 2008). Hospitals are expected to spend all available resources to maximize the quality and accessibility of health care to society, instead of creating high positive earnings.
Leone and Van Horn (2005) provide evidence that nonprofit hospital CEOs manage earnings to a range just above zero. Hoerger (1991) explains that this ‘just above zero’ earnings benchmark is optimal for hospitals because they attempt to achieve a target level of earnings that satisfies the budget constraint of zero. Arising from the prospect theory, the cost of reporting a loss of 1 euro is higher than reporting a 1 euro gain (Kahneman and Tversky 1979). Therefore, hospital CEOs will take actions that lead to earnings just above zero.
EARNINGS MANAGEMENT IN DUTCH HOSPITALS
In the DTC payment system, hospitals keep or lose the difference between the diagnosis related group (DRG) rate and their actual costs. Hospitals can hardly estimate in advance which and how many medical and supporting services a patient needs, and thus what the treatment costs are for that specific patient, while reimbursement is fixed. Therefore, earnings under the DTC payment system are more uncertain compared to the external budget funding in combination with the retrospective cost-based system. Due to the earnings uncertainty, managers need to care more about their reputation and are thus more likely to manage earnings in their best interests.
Furthermore, Schaepkens (2004) argues that market competition will lead to more earnings management in hospitals. Under the DTC system, hospital CEOs might not want to disclose their true economic performance because of the increased competition. After the transition of the external budget funding in combination with the retrospective cost-based system to the DTC payment system, the market competition has increased due to the negotiable DTCs in the B-segment. Hence, the expectation is that hospitals engage more in earnings management since the introduction of the DTC payment system.
Research question: What are the effects of the introduction of the Diagnosis Treatment Combination payment system in Dutch hospitals on earnings management?
Previous research (Leone and Van Horn 2005; Hoerger 1991) provides evidence that hospital CEOs manage earnings towards a ‘just above zero’ benchmark. For hospital CEOs, there are incentives as well as opportunities to apply this pattern of earnings management. According to Bouwens et al (2006), CEOs of Dutch hospitals manage earnings towards the ‘just above zero’ benchmark. They found significant evidence that there are less results observed below break-even compared to results observed with positive earnings or high losses. If hospital CEOs manage earnings more to this ‘just above zero’ benchmark since the introduction of the DTC payment system, a more non-normal distribution of net operating income will be observed with unusually low frequencies just to the left of the break-even point and unusually high frequencies just to the right of the break-even point. Thus, I put:
Hypothesis 1: Dutch hospitals engage more in earnings management since the Diagnosis Treatment Combination payment system is introduced, to manage earnings towards the ‘just above zero’ benchmark.
For earnings management toward the ‘just above zero’ earnings benchmark to occur, at some point during the fiscal year, the hospital CEO must realize that financial performance will miss the benchmark. After that realization, hospital CEOs have different options to manage reported earnings towards the ‘just above zero’ benchmark.
One possibility is to influence hospitals’ financial performance by real activity manipulations. Real activity manipulation occurs when managers undertake actions that change the timing or structuring of an operation, investment and/or financing transaction in an effort to manage reported earnings (Gunny 2010). Examples of real activity earnings management in hospitals are discretionary spending and asset disposal (Eldenburg et al. 2006), research and development expenses (Baber et al. 1991), cost shifting (Krishnan and Yetman 2011) and especially important since the introduction of the DTC payment system the ‘upcoding’ of patient DRGs (Silverman and Skinner 2004; Heese et al. 2012). According to Gunny (2010) firms use real activities manipulation to report small positive earnings, instead of reporting a loss.
Another possibility for hospitals is to adjust accounting accruals using the flexibility and subjective nature inherent in Generally Accepted Accounting Principles (GAAP), which has previously been investigated by various researchers (e.g. Healy and Wahlen 1999; Leone and Van Horn 2005). Accrual management involves the choice of accounting methods that try to ‘obscure’ or ‘mask’ true economic performance (Dechow and Skinner 2000).
Earnings management via accounting accruals is much less costly than managing real activities. Also, accrual management can take place after the end of the fiscal year when the need for earnings management is the most certain, whereas real activity earnings management decisions must be made prior to fiscal year end (Gunny 2010). Therefore, in this study, the use of accruals will be evaluated to investigate earnings management under the new DTC payment system. Discretionary accruals are the most common used technique to measure earnings management within the health care industry (e.g. Lee, Mesia and Griflin 2014; Leone and Van Horn 1999; Leone and Van Horn 2005). The expectation is that hospital CEOs make income-increasing accruals when earnings are negative, and make income-decreasing accruals to get closer to zero when earnings are positive. Thus, I put:
Hypothesis 2: Dutch hospitals engage more in accrual management since the Diagnosis Treatment Combination payment system is introduced, to manage earnings towards the ‘just above zero’ benchmark.
RESEARCH METHOD
‘JUST ABOVE ZERO’ BENCHMARK
According to Burgstahler and Dichev (1997), 30-44% of organizations with pre-managed losses manage earnings to create positive reported earnings. They showed two types of evidence, graphical and formal statistical, for the prevalence of earnings management to avoid losses.
To test the hypothesis that Dutch hospitals engage more in earnings management since the Diagnosis Treatment Combination payment system is introduced, an graphical and an formal statistical test, as described in Burgstahler and Dichev (1997), will be used.
First, graphical evidence in the form of histograms of the distributions of scaled earnings levels will be presented, to analyze the behavior of reported earnings around zero. Earnings will be scaled by total assets, which makes it possible to compare the hospitals in the sample. If hospital CEOs engage in earnings management to move earnings towards the ‘just above zero’ benchmark, a non-normal distribution of reported earnings with unusually low frequencies to the left of zero and unusually high frequencies just to the right of zero will be observed (Degeorge et al. 1999). The expectation is that earnings management has increased after the introduction of the DTC payment system, and thus that scaled earnings are more non-normal distributed than before the introduction of the reimbursement system.
Second, a formal statistical test will be presented to examine the following hypothesis:
Hypothesis 1: Dutch hospitals engage more in earnings management since the Diagnosis Treatment Combination payment system is introduced, to manage earnings towards the ‘just above zero’ benchmark.
To test the hypothesized increase of earnings management towards the ‘just above zero’ benchmark after the introduction of the DTC payment system, a paired sample t-test will be performed. This is a statistical test to examine whether earnings management differs significantly before and after the introduction of the DTC payment system.
Null hypothesis: H_0 : x ??_1 = x ??_2
where,
x ??_1 Mean for the scaled earnings sample after the introduction of the DTC payment system;
x ??_2 Mean for the scaled earnings sample before the introduction of the DTC payment system.
Alternative hypothesis: H_1 : x ??_1 ‘ x ??_2
The formula to conduct the t-test and to test whether Dutch hospitals engage more in earnings management since the Diagnosis Treatment Combination payment system is introduced, is as follows:
t = (x ??_1- x ??_(2 ) )/(s1/'(n_1 ) – s_2/'(n_2 ))
where,
x ??_1 Mean for the scaled earnings sample after the introduction of the DTC payment system;
x ??_2 Mean for the scaled earnings sample before the introduction of the DTC payment system;
s_1 Standard deviation for the scaled earnings sample after the introduction of the DTC payment system;
s_2 Standard deviation for the scaled earnings sample before the introduction of the DTC payment system;
n_1 Sample size for the scaled earnings sample after the introduction of the DTC payment system;
n_2 Sample size for the scaled earnings sample before the introduction of the DTC payment system.
ACCRUAL MANAGEMENT
To test the hypothesis that Dutch hospitals engage more in accrual management since the Diagnosis Treatment Combination payment system is introduced, I will make use of the Modified Jones model.
In 1991, Jones developed a new model to measure earnings management. For this, she used a method in which the difference between net income and operating cash flows leads towards the total of accruals. According to Jones (1991), total accruals consists of the change in current assets other than cash and short-term investments less current liabilities other than current maturities of long-term liabilities less total depreciation expense. The Jones Model had the weakness that changes in sales were not adjusted for changes in receivables. Therefore, Dechow et al. (1995) revised the Jones model and developed the Modified Jones model. To test hypothesis 2, the Modified Jones model will be used, since this model has been shown to be the most powerful among competing models for detecting earnings management (e.g. Klein 2002).
Consistent with discretionary accrual estimation in prior research (Jones 1991), total accruals are computed as:
‘TA’_(j,t) = (”CA’_(j,t) – ”CL’_(j,t) – ”Cash’_(j,t)+ ”STD’_(j,t) – ‘Dept’_(j,t) ) / A_(j,t-1)
where,
‘TA’_(j,t) Total accruals for hospital j in year t;
”CA’_(j,t) Change in current assets for hospital j in year t;
”CL’_(j,t) Change in current liabilities for hospital j in year t;
”Cash’_(j,t) Change in cash and cash equivalents for hospital j in year t;
”STD’_(j,t) Change in current maturities of long-term liabilities for hospital j in year t;
‘Dept’_(j,t) Depreciation and amortization expense for hospital j in year t;
A_(j,t-1) Total assets hospital j in year t-1.
In the Modified Jones model, nondiscretionary accruals are measured using the following regression model:
(‘NDA’_(j,t) )’A_(j,t-1) =a_(j,t) (1’A_'(j,t-1@ ) )+b_(1j,t) ((”REV’_(j,t)- ”REC’_(j,t))’A_'(j,t-1) )+ b_(2j,t) (‘PPE’_(j,t)’A_(j,t-1 ) )
where,
‘NDA’_(j,t) Nondiscretionary accruals for hospital j in year t;
A_(j,t-1) Total assets for hospital j in year t-1;
a_(j,t) A constant for hospital j that needs to be estimated;
b_(1j,t) A constant for hospital j that needs to be estimated;
”REV’_(j,t) Change in revenues for hospital j in year t;
”REC’_(j,t) Change in net receivables for hospital j in year t;
b_(2j,t) A constant for hospital j that needs to be estimated;
‘PPE’_(j,t) Total property, plant and equipment for hospital j in year t, scaled by total assets at t-1.
Thereafter, discretionary accruals are obtained by subtracting nondiscretionary accruals in year t from total accruals in year t (Guay et al. 1996):
‘DA’_(j,t) = ‘TA’_(j,t) – ‘NDA’_(j,t)
where,
‘DA’_(j,t) Discretionary accruals for hospital j in year t;
‘TA’_(j,t) Total accruals for hospital j in year t;
‘NDA’_(j,t) Nondiscretionary accruals for hospital j in year t.
To test hypothesis 2, discretionary accruals prior to the introduction of the DTC payment system will be compared to discretionary accruals after the introduction of the DTC payment system. The expectation is that Dutch hospitals engage more in accrual management since the DTC payment system is introduced, to manage earnings towards the ‘just above zero’ benchmark.
SAMPLE SELECTION AND DATA
The initial population of this research consists of all hospitals in the Netherlands for the fiscal years 2003 till 2006, which implies two years before the introduction of the DTC payment system and two years after the introduction. According to Dutch Hospital Data, who annually present statistics about the hospital industry in the Netherlands, there were 145 hospitals in the Netherlands and the end of 2006. Therefore, the initial sample size amounts to 580 fiscal year observations.
At the end of 2006, there were 85 general hospitals, 8 academic hospitals, 35 categorical hospitals, and 17 rehabilitation centers (Dutch Hospital Data 2007). Categorical hospitals are mostly focused on one type of care (e.g. abortion and cancer). The same applies to rehabilitation centers, which has a primary focus on rehabilitative care. The DTC payment system was introduced as of 2006 for categorical hospitals, and as of 2009 for rehabilitation centers. For that reason, all categorical hospitals and rehabilitation centers are excluded from the final sample. Furthermore, due to the involvement with mergers over the years of observation, a total of x hospitals and x fiscal year observations had to be excluded, leading to a final sample size of x hospitals and x fiscal year observations. [invullen na het verzamelen van de data]
Sample size Number of observations Number of hospitals
Initial sample size 580 145
Less:
Categorical hospitals 140 35
Rehabilitation centers 68 17
Hospitals involved with mergers
Final sample size
Verzamelen:
Reported earnings 2003, 2004, 2005, 2006
Reported revenues 2002, 2003, 2004, 2005, 2006
Total assets 2002, 2003, 2004, 2005, 2006
Current liabilities 2002, 2003, 2004, 2005, 2006
Current maturities of long-term liabilities 2002, 2003, 2004, 2005, 2006
Depreciation and amortization expense 2003, 2004, 2005, 2006
Net receivables 2002, 2003, 2004, 2005, 2006
PPE 2003, 2004, 2005, 2006
REFERENCES
Baber, W.R., P.M. Fairfield, and J.A. Haggard. 1991. The Effect of Concern about Reported Income on Discretionary Spending Decisions: the Case of Research and Development. The Accounting Review 66 (4): 818-829.
Ballantine, J., J. Forker, and M. Greenwood. 2008. The Governance of CEO Incentives in English NHS Hospital Trusts. Financial Accountability and Management 24 (4): 385-410.
Bouwens, J., S. Hollander, and F. Schaepkens. 2006. Earnings Management in Dutch Hospitals: Controlled Evidence. Tilburg University Working Paper.
Brickley, J.A., and R.L. Van Horn. 2002. Managerial Incentives in Nonprofit Organizations: Evidence from Hospitals. Journal of Law and Economics 45 (1): 227-249.
Burgstahler, D., and I. Dichev. 1997. Earnings Management to Avoid Earnings Decreases and Losses. Journal of Accounting and Economics 24 (1): 99-126.
Cornell, B., and A.C. Shapiro. 1987. Corporate Stakeholders and Corporate Finance. Financial Management 16 (1): 5-14.
Dechow, P.M., R.G. Sloan, and A.P. Sweeney. 1995. Detecting Earnings Management. Accounting Review 70 (2): 193-225.
Dechow, P.M., and D.J. Skinner. 2000. Earnings Management: Reconciling the Views of Accounting Academics, Practitioners, and Regulators. Accounting Horizons 14(2): 235-250.
Degeorge, F., J. Patel, and R. Zeckhauser. 1999. Earnings Management to Exceed Thresholds. Journal of Business 72 (1): 1-33.
Dutch Hospital Data. 2007. Kengetallen Nederlandse Ziekenhuizen 2007.
Eldenburg, L.G., K.A. Gunny, K.W. Hee, and N. S??derstr??m. 2011. Earnings Management Using Real Activities: Evidence from Nonprofit Hospitals. The Accounting Review 86 (5): 1605-1630.
Guay, W.R., S.P. Kothari, and R.L. Watts. 1996. A Market-based Evaluation of Discretionary Accrual Models. Journal of Accounting Research 34: 83-105.
Gunny, K.A. 2010. The Relation Between Earnings Management Using Real Activities Manipulation and Future Performance: Evidence from Meeting Earnings Benchmarks. Contemporary Accounting Research 27: 855-888.
Guterman, S., and A. Dobson. 1986. Impact of the Medicare Prospective Payment System for Hospitals. Health Care Financial Review 7 (3): 97-114.
Hayn, C. 1995. The Information Content of Losses. Journal of Accounting and Economics 20 (2): 125-153.
Healy, P.M., and J.M. Wahlen. 1999. A Review of the Earnings Management Literature and its Implications for Standard Setting. Accounting Horizons 13 (4): 365-383.
Heese, J., R. Krishnan, and F. Moers. 2012. Regulator Leniency and Mispricing in Beneficent Nonprofits. Harvard Business School Accounting & Management Unit Working Paper No. 15-056.
Hoerger, T.J. 1991. ‘Profit’ Variability in For-Profit and Not-For-Profit Hospitals. Journal of Health Economics 10 (3): 259-289.
Jones, J.J. 1991. Earnings Management During Import Relief Investigations. Journal of Accounting Research 29 (2): 193-228.
Kahneman, D., and A. Tversky. 1979. Prospect Theory: an Analysis of Decision under Risk. Econometrica 47 (2): 263-292.
Klein, A. 2002. Audit Committee, Board of Director Characteristics, and Earnings Management. Journal of Accounting and Economics 33 (3): 375-400.
Krishnan, R., and M.H. Yetman. 2011. Institutional Drivers of Reporting Decisions in Nonprofit Hospitals. Journal of Accounting Research 49 (4): 1001-1039.
Lee, K.Y., R. Mesia and T. Griffin. 2014. Motivational Factors Affecting Earnings Management of Not-for-profit Hospitals in South Korea. Research Journal of Business Management 8: 1-27.
Leone, A.J., and R.L. Van Horn. 1999. Earnings Management in Not-For-Profit Institutions: Evidence from Hospitals. Simon School of Business Working Paper FR 99-03.
Leone, A.J, and R.L. Van Horn. 2005. How Do Nonprofit Hospitals Manage Earnings? Journal of Health Economics 24 (4): 815-837.
Maarse, H., and Y. Bartholom??e. 2006. A Public-Private Analysis of the New Dutch Health Insurance System. The European Journal of Health Economics 8 (1): 77-82.
Schaepkens, F.F.J.M. 2004. Marktwerking in de ziekenhuiszorg: enige beschouwingen. MCA Tijdschrift voor Organisaties in Control.
Schipper, K. 1989. Commentary on Earnings Management. Accounting Horizons 3 (4): 91-102.
Silverman, E., and J. Skinner. 2004. Medicare Upcoding and Hospital Ownership. Journal of Health Economics 23 (2): 369-389.
S??derstr??m, N. 1990. Are Reporting Errors under PPS Random or Systematic? Inquiry 27 (3): 234-241.
Van de Ven, W.P.M.M., and F.T. Schut. 2008. Universal Mandatory Health Insurance in the Netherlands: a Model for the United States? Health Affairs 27 (3): 771-781.
Van Herck, G. 2003. Zijn ziekenhuizen minder ‘creatief’ in accounting? Tijdschrift voor Economie en Management. XLVIII (2).