Choosing the Number of Instruments

Properties of instrumental variable estimators are sensitive to the choice of valid instruments, even in large cross‐section applications. In this paper we address this problem by deriving simple mean‐square error criteria that can be minimized to choose the instrument set. We develop these criteria for two‐stage least squares (2SLS), limited information maximum likelihood (LIML), and a bias adjusted version of 2SLS (B2SLS). We give a theoretical derivation of the mean‐square error and show optimality. In Monte Carlo experiments we find that the instrument choice generally yields an improvement in performance. Also, in the Angrist and Krueger (1991) returns to education application, when the instrument set is chosen in the way we consider, it turns out that both 2SLS and LIML give similar (large) returns to education.     

Semiparametric inference for estimating equations with nonignorably missing covariates

We consider statistical inference of unknown parameters in estimating equations (EEs) when some covariates have nonignorably missing values, which is quite common in practice but has rarely been discussed in the literature. When an instrument, a fully observed covariate vector that helps identifying parameters under nonignorable missingness, is available, the conditional distribution of the missing covariates given other covariates can be estimated by the pseudolikelihood method of Zhao and Shao [(2015), ‘Semiparametric pseudo likelihoods in generalised linear models with nonignorable missing data’, Journal of the American Statistical Association, 110, 1577–1590)] and be used to construct unbiased EEs. These modified EEs then constitute a basis for valid inference by empirical likelihood. Our method is applicable to a wide range of EEs used in practice. It is semiparametric since no parametric model for the propensity of missing covariate data is assumed. Asymptotic properties of the proposed estimator and the empirical likelihood ratio test statistic are derived. Some simulation results and a real data analysis are presented for illustration.     

Techniques and paradoxes in performing performance measurements: concluding reflections

ABSTRACT

Performance measurement has an implicit performance theory embedded within its practice; performance measurement perforce performs. Performance measurement has a performative effect on performance. Drawing together and building on the various empirical observations from the preceding papers in this collection, this concluding paper firstly examines the circumstances in which performance measurement performs, that is, when it produces ‘authentic’ performance improvements, compared to when performance measurements misfire. The paper secondly explores several paradoxes of performance measurement – such that performance measurement measures only part of the performance it seeks to be performative on, incentives to perform incentivise poor performance and so on. These paradoxes, contradictions and ironies must be apprehended and appreciated in discovering, discerning and deciphering the diverse dynamics of measuring performance. They also demonstrate that analysing and working with performance measurement requires a perspective that eschews absolutes and clear directions, and embraces the uneasy and potentially destabilising tension of Escher’s performative art.     

Hitting the target without missing the point: New Zealand’s immunisation health target for two year olds

ABSTRACT

The use of health targets as a form of performance measurement has become more prominent internationally as governments have sought to control public expenditure, produce greater efficiency and improve accountability. However, health targets have faced criticism for their potential to produce negative outcomes within a health system. This paper examines how a health target was used as a policy instrument within the New Zealand health system to improve immunisation coverage at two years of age. It explores how the immunisation health target was implemented within four case study sites and discusses the effectiveness of the health target as a policy instrument for improving immunisation coverage and addressing persistent immunisation inequities. Measuring and monitoring performance towards the immunisation health target improved accountability for immunisation coverage within the New Zealand health system and focused attention on improving immunisation coverage in a way that previous policy attempts had failed to do. Health targets may be an effective policy instrument for creating change within specific areas of a health system if their potential for dysfunctional consequences are taken into consideration at the outset.     

Development and Utilization of a Practice-Based,Adolescent Intake Questionnaire (Adquest)

Summary

This article describes an intake questionnaire (Adquest) that was designed, tested, and implemented, and later employed in clinical data-mining studies, by practitioners in an adolescent mental health program. The instrument is primarily a practice-based, clinical information-gathering and client engagement device. Consequently, it differs in significant ways from more research-driven Rapid Assessment Instruments (RAIs). Despite these differences, when aggregated and analyzed, Adquest data provides valuable psychosocial information about hundreds of vulnerable urban youth seeking mental health services.     

Assessment of the Refined Aging Semantic Differential: Recommendations for Enhancing Validity

The US population is aging. Traditional perspectives have emphasized that a substantial increase in the number of gerontological social workers is needed to care for this population. However, published evidence demonstrates that, along with population growth, economic and social factors must be taken into account before predicting future gerontological social work demand. Structural lag theory is introduced to explain how these factors affect the profession and may limit its presence in gerontological work settings. Recommendations are made to correct the lag, allowing the social work profession a more substantive voice in the aging enterprise.     

关于消费者对促销的反应行为研究

不同类型的促销工具在导致消费者产生特定反应行为方面具有差异性。针对消费者品牌转换行为最有效的促销工具是价格折扣和样品赠送;针对消费者购买加速行为最有效的促销工具是价格折扣与购物赠礼;针对消费者增加购买量最有效的促销工具是价格折扣;针对消费者产品试用行为最有效的促销工具是价格折扣、样品赠送、购物赠礼;购物抽奖相对来说促销效果最差。营销者应根据企业目标针对性地选择最合适的促销工具。     

Cross-Cultural Analyses of Determinants of Quality of Life and Mental Health: Results from the Eurohis Study

Recent projects on international instrument development have produced a wide array of health indicators that may be used for cross-cultural field-testing, however more information on their cross-cultural performance in relation to health determinants is necessary. The current study approaches one step for international conceptual validation by analysing the association between various health determinants and different types of health outcomes (mental health, quality of life) across a range of countries or geographical areas. The current study is based on the EUROHIS project that has been conducted in a sample of 4849 adults across 10 European countries. Results highlight that interactions between health determinants with subjective mental health, general health and quality of life (QoL) differ between Western European countries, Eastern European countries and the Newly Associated States as well as Israel. Using a MIMIC model approach, we were able to show that the impact of each of the sociodemographic variables cannot be interpreted on the basis of its single loading but only seeing the interacting with other indicators. Future studies should include sociodemographics in MIMIC models in each latent factor before carrying out regressions on a larger scale. Future investigations will require larger and representative samples to (a) test models on latent factors of mental health and QoL and (b) on the basis of these findings test overall structural models across countries.     

基于DSP与LabVIEW仿生运动机理模型在线切换、离散化系统

仿生运动机理模型在实际的应用过程中,必须针对特定的应用场合和不同的硬件系统选择不同的控制模型和最优参数,使实际效果达到最佳。文章提出了一种基于DSP与LabVIEW,对仿生运动机理模型进行实时在线离散化的方法。该方法实现了控制模型的在线切换、参数的实时修正、模型的在线离散化、LabVIEW和DSP的实时通信。实验结果表明,该系统实时性好、运行可靠。