Resampling DEA estimates of investment fund performance

This article was submitted for publication in the serial European Journal of Operational Research [© Elsevier]. The definitive version is available at:http://dx.doi.org/10.1016/j.ejor.2012.07.015Data envelopment analysis (DEA) is attractive for comparing investment funds because it handles different characteristics of fund distribution and gives a way to rank funds. There is substantial literature applying DEA to funds, based on the time series of funds' returns. This article looks at the issue of uncertainty in the resulting DEA efficiency estimates, investigating consistency and bias. It uses the bootstrap to develop stochastic DEA models for funds, derive confidence intervals and develop techniques to compare and rank funds and represent the ranking. It investigates how to deal with autocorrelation in the time series and considers models that deal with correlation in the funds' returns. © 2012 Elsevier B.V. All rights reserved

Neonatal hearing screening: modelling cost and effectiveness of hospital- and community-based screening

BACKGROUND: Children with congenital hearing impairment benefit from early detection and management of their hearing loss. These and related considerations led to the recommendation of universal newborn hearing screening. In 2001 the first phase of a national Newborn Hearing Screening Programme (NHSP) was implemented in England. Objective of this study was to assess costs and effectiveness for hospital and community-based newborn hearing screening systems in England based on data from this first phase with regard to the effects of alterations to parameter values. METHODS: Design: Clinical effectiveness analysis using a Markov Model. Outcome measure: quality weighted detected child months (QCM). RESULTS: Both hospital and community programmes yielded 794 QCM at the age of 6 months with total costs of £3,690,000 per 100,000 screened children in hospital and £3,340,000 in community. Simulated costs would be lower in hospital in 48% of the trials. Any statistically significant difference between hospital and community in prevalence, test sensitivity, test specificity and costs would result in significant differences in cost-effectiveness between hospital and community. CONCLUSION: This modelling exercise informs decision makers by a quantitative projection of available data and the explicit and transparent statements about assumptions and the degree of uncertainty. Further evaluation of the cost-effectiveness should focus on the potential differences in test parameters and prevalence in these two settings

Cost-effectiveness analysis of cognitive behaviour therapy for treatment of minor or mild-major depression in elderly patients with type 2 diabetes: study protocol for the economic evaluation alongside the MIND-DIA randomized controlled trial (MIND-DIA CEA)

<p>Abstract</p> <p>Background</p> <p>Depression and elevated depression symptoms are more prevalent in patients with type 2 diabetes than in those without diabetes and are associated with adverse health outcomes and increased total healthcare utilization. This suggests that more effective depression treatment might not only improve health outcome, but also reduce costs. However, there is a lack of evidence on (cost-) effectiveness of treatment options for minor and mild-major depression in patients with type 2 diabetes. In this paper we describe the design and methods of the economic evaluation, which will be conducted alongside the MIND-DIA trial (Cognitive behaviour therapy in elderly type 2 diabetes patients with minor or mild-major depression). The objective of the economic evaluation (MIND-DIA CEA) is to examine incremental cost-effectiveness of a diabetes specific cognitive behaviour group therapy (CBT) as compared to intensified treatment as usual (TAU) and to a guided self-help group intervention (SH).</p> <p>Methods/Design</p> <p>Patients will be followed for 15 months. During this period data on health sector costs, patient costs and societal productivity/time costs will be collected in addition to clinical data. Person-years free of moderate/severe major depression, quality adjusted life years (QALYs), and cumulative costs will be estimated for each arm of the trial (CBT, TAU and SH). To determine cost-effectiveness of the CBT, differences in costs and effects between the CBT group and TAU/SH group will be calculated.</p> <p>Discussion</p> <p>CBT is a potentially effective treatment option to improve quality of life and to avoid the onset of a moderate/severe major depression in elderly patients with type 2 diabetes and minor or mild-major depression. This hypothesis will be evaluated in the MIND-DIA trial. Based on these results the associated economic evaluation will provide additional evidence on the cost-effectiveness of CBT in this target population. Methodological strengths and weaknesses of the planned economic evaluation are discussed.</p> <p>Trial registration</p> <p>The MIND-DIA study has been registered at the Current Controlled Trials Register (ISRCTN58007098).</p

Within-trial economic evaluation of diabetes-specific cognitive behaviour therapy in patients with type 2 diabetes and subthreshold depression

<p>Abstract</p> <p>Background</p> <p>Despite the high prevalence of subthreshold depression in patients with type 2 diabetes, evidence on cost-effectiveness of different therapy options for these patients is currently lacking.</p> <p>Methods/Design</p> <p>Within-trial economic evaluation of the diabetes-specific cognitive behaviour therapy for subthreshold depression. Patients with diabetes and subthreshold depression are randomly assigned to either 2 weeks of diabetes-specific cognitive behaviour group therapy (n = 104) or to standard diabetes education programme only (n = 104). Patients are followed for 12 months. During this period data on total health sector costs, patient costs and societal productivity costs are collected in addition to clinical data. Health related quality of life (the SF-36 and the EQ-5D) is measured at baseline, immediately after the intervention, at 6 and at 12 months after the intervention. Quality adjusted life years (QALYs), and cumulative costs will be estimated for each arm of the trial. Cost-effectiveness of the diabetes-specific cognitive behaviour group therapy will be analysed from the perspective of the German statutory health insurance and from the societal perspective. To this end, incremental cost-effectiveness ratio (ICER) in terms of cost per QALY gained will be calculated.</p> <p>Discussion</p> <p>Some methodological issues of the described economic evaluation are discussed.</p> <p>Trial registration</p> <p>The trial has been registered at the Clinical Trials Register (NCT01009138).</p

Patient involvement in improving the evidence base on mental health inpatient care: the PERCEIVE programme

BackgroundDespite the movement towards care in the community, 40% of the NHS budget on mental health care is still attributed to inpatient services. However, long before the Francis Report highlighted grave shortcomings in inpatient care, there were reports by service user groups on the poor quality of these services in mental health. The programme provides a particular focus on the inclusion of the patient’s perspective in the development and evaluation of evidence.ObjectivesTo understand how changes to inpatient care affect the perceptions of the ward by service users and staff by using stakeholder participatory methods.DesignThe programme consisted of four work packages (WPs). (1) Lasting Improvements for Acute Inpatient SEttings (LIAISE): using participatory methods we developed two new scales [Views On Therapeutic Environment (VOTE) for staff and Views On Inpatient CarE (VOICE) for service users]. (2) Client Services Receipt Inventory – Inpatient (CITRINE): working with nurses and service users we developed a health economic measure of the amount of contact service users have with staff. The self-report measure records interactions with staff as well as the number of therapeutic activities attended. (3) Delivering Opportunities for Recovery (DOORWAYS): a stepped-wedge randomised controlled trial to test if training ward nurses to deliver therapeutic group activities would improve the perception of the ward by service users and staff. A total of 16 wards were progressively randomised and we compared the VOICE, VOTE and CITRINE measures before and after the intervention. A total of 1108 service users and 539 staff participated in this trial. (4) Bringing Emergency TreatmenT to Early Resolution (BETTER PATHWAYS) was an observational study comparing two service systems. The first was a ‘triage’ system in which service users were admitted to the triage ward and then either transferred to their locality wards or discharged back into the community within 7 days. The second system was routine care. We collected data from 454 service users and 284 nurses on their perceptions of the wards.Main outcome measuresThe main outcomes for the DOORWAYS and BETTER project were service user and staff perceptions of the ward (VOICE and VOTE, respectively) and the health economic measure was CITRINE. All were developed in WPs 1 and 2.ResultsWe developed reliable and valid measures of (1) the perceptions of inpatient care from the perspectives of service users and nurses (VOICE and VOTE) and (2) costs of interactions that were valued by service users (CITRINE). In the DOORWAYS project, after adjusting for legal status, we found weak evidence for benefit (standardised effect of –0.18, 95% CI 0.38 improvement to 0.01 deterioration; p = 0.062). There was only a significant benefit for involuntary patients following the staff training (N582, standardised effect of –0.35, 95% CI –0.57 to –0.12; p = 0.002; interaction p-value 0.006). VOTE scores did not change over time (standardised effect size of 0.04, 95% CI –0.09 to 0.18; p = 0.54). We found no evidence of an improvement in cost-effectiveness (estimated effect of £33, 95% CI –£91 to £146; p = 0.602), but resource allocation did change towards patient-perceived meaningful contacts by an average of £12 (95% CI –£76 to £98; p = 0·774). There were no significant differences between the triage and routine models of admission in terms of better perceptions by service users (estimated effect 0.77-point improvement in VOICE score on the triage ward; p = 0.68) or nurses (estimated effect of 1.68-point deterioration in VOTE on the triage ward; p = 0.38) or in terms of the cost of the length of care provided (£391 higher on triage; p = 0.77).Strengths and limitationsWe have developed measures using methods involving both service users and staff from mental health services. The measures were developed specifically for acute inpatient services and, therefore, cannot be assumed to be useful for other services. For instance, extensions of the measures are under construction for use in mother and baby units. The strength of the BETTER PATHWAYS and DOORWAYS projects is the large-scale data collection. However, we were testing specific services based in inner city areas and stretching to inner urban areas. It may be that different effects would be found in more rural communities or in different types of inpatient care.Future workOur database will be used to develop an understanding of the mediating and moderating factors for improving care quality.Trial registrationCurrent Controlled Trials ISRCTN06545047.FundingThis project was funded by the NIHR Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 6, No. 7. See the NIHR Journals Library website for further project information

A classification of DEA models when the internal structure of the Decision Making Units is considered

We classify the contributions of DEA literature assessing Decision Making Units (DMUs) whose internal structure is known. Starting from an elementary framework, we define the main research areas as shared flow, multilevel and network models, depending on the assumptions they are subject to. For each model category, the principal mathematical formulations are introduced along with their main variants, extensions and applications. We also discuss the results of aggregating efficiency measures and of considering DMUs as submitted to a central authority that imposes constraints or targets on them. A common feature among the several models is that the efficiency evaluation of the DMU depends on the efficiency values of its subunits thereby increasing the discrimination power of DEA methodology with respect to the black box approach

Maximum likelihood estimation in signal analysis of MR spectroscopy

Proton magnetic resonance spectroscopy (MRS) is used to determine the concentration of metabolites in organic tissues, or to study metabolic changes in a non-invasive way. The complex-valued magnetic resonance spectroscopy signals are assumed to be disturbed by additive white noise. The distributional properties of the stochastic noise are studied. A statistical model for the magnitude and phase of the Fourier transformed magnetic resonance spectroscopy signal is introduced. Maximum likelihood estimators of the distributional parameters of this model are derived and asymptotic properties such as consistency, asymptotic normality and efficiency of the estimators are verified. A simulation study is used to test the findings and the model is tested on magnetic resonance spectroscopy data from a spectroscopy phantom and human brain data