Measurement of patient-reported outcomes. 1: The search for the Holy Grail

Abstract

Patient-reported outcome measures (PROMs) are used to collect information directly from patients. They may cover several different types of outcomes ranging from symptoms, functioning, utility, satisfaction, through to quality-of-life (QoL). They generally consist of self-completed questionnaires that can be administered by means of hard copies or in a range of electronic formats. PROMs vary considerably in terms of the constructs they assess, the care with which they are developed, and their scientific quality. However, none of the PROMs available approach the quality of measurement achieved by measures/instruments used in physics. PROs are examples of latent variables. These are not directly observable, but can be inferred from, for example, responses to a questionnaire. The only measure of a latent variable that approaches the quality of measurement achieved by the physical sciences is the Lexile Framework for Reading. This framework is based on a construct theory that grew out of an analysis of several available reading measures. A specification equation was generated that was able to link the construct theory to scores obtained with the Lexile measure. A fundamental requirement of this quality of measurement is that the data collected with the model fit Rasch Measurement Theory (RMT). It is argued that PROM developers should aspire to match this level of measurement sophistication if their instruments are to provide valid insights into the impacts of disease and its treatment.     

全站仪的误差分析及精度控制在水利工程测量中的研究

水利工程是国民经济建设过程中非常重要的建设内容,能够为人们的生产生活提供极大的便利,这就需要保证水利工程测量工作的准确性。在水利工程测量过程中,常用的测量工具就是全站仪,做好其误差分析与精度控制工作是非常必要的,本文就主要针对此予以简单分析。     

Using Machine Learning for measuring democracy: A practitioners guide and a new updated dataset for 186 countries from 1919 to 2019

We provide a comprehensive overview of the literature on the measurement of democracy and present an extensive update of the Machine Learning indicator of Gründler and Krieger (2016). Four improvements are particularly notable: First, we produce a continuous and a dichotomous version of the Machine Learning democracy indicator. Second, we calculate intervals that reflect the degree of measurement uncertainty. Third, we refine the conceptualization of the Machine Learning Index. Finally, we significantly expand the data coverage by providing democracy indices for 186 countries in the period from 1919 to 2019.     

How do indicators of household food insecurity measure up? An empirical comparison from Ethiopia

Renewed emphasis on programs and policies aimed at enhancing food security has intensified the search for accurate, rapid, and consistent indicators. Measures of food security are urgently required for purposes of early warning, assessment of current and prospective status of at-risk populations, and monitoring and evaluation of specific programs and policies. Different measures are often used interchangeably, without a good idea of which dimensions of food security are captured by which measures, resulting in potentially significant misclassification of food insecure populations. The objective of this paper is to compare how the most frequently used indicators of food security portray static and dynamic food security among the same sample of rural households in two districts of Tigray State, Northern Ethiopia. Seven food security indicators were assessed: the Coping Strategies Index (CSI); the Reduced Coping Strategies Index (rCSI); the Household Food Insecurity and Access Scale (HFIAS); the Household Hunger Scale (HHS); Food Consumption Score (FCS); the Household Dietary Diversity Scale (HDDS); and a self-assessed measure of food security (SAFS). These indicators provide very different estimates of the prevalence of food insecurity, but are moderately well correlated and depict generally similar food security trends over time. We suggest that the differences in prevalence estimates, and in some cases the weaker than expected correlation, can be explained in three ways. First, the indicators differ in the underlying aspect of food security they attempt to capture. Second, each indicator is likely only sensitive within a certain severity range of food insecurity and these ranges do not always overlap. Third, categorization of the prevalence of food insecurity is strongly dependent on the choice of cut-off points. For valid reasons, “food insecurity” has no accepted gold standard metric against which individual indicators can be gauged, though without one it is difficult to say which indicator performs “best” in correctly and reliably identifying food insecure households. The implication is that using more than one indicator is advisable, and policy makers should be aware of what elements of food insecurity each indicator portrays.     

Modeling asymmetric price transmission in the European food market

In this study, we employ a multivariate panel error correction model (PVECM) to investigate asymmetric price transmission among the farm, processor, and retail segments of the European food supply chain for the 2005–2016 period. The results indicate that, in both the long- and short-run, retail prices respond more strongly to processor price increases than decreases and the same occurs for processor prices due to farm price changes. Thus, the findings demonstrate the presence of positive asymmetric price transmission in the European food supply chain. Finally, the results of the present study indicate that the food price pass-through varies greatly across product category and across countries, and that the pass-through to producer prices is greater than that to consumer prices.     

双选信道下一种基于混沌交织的FBMC系统

高速移动环境下，无线信道具有时频双选性衰落的特性，使得滤波器组多载波(Filter Bank Multi-carrier，FBMC)系统产生长突发差错。将一种基于Baker映射的混沌交织算法应用在滤波器组多载波系统中，根据混沌密钥对发送数据进行分块和重新排列，按照Baker映射规则完成数据交织。此方法可以将长突发差错变为单突发差错，结合卷积编码能有效地纠正双选信道产生的长突发差错。仿真结果表明，在双选择信道中，基于混沌交织的滤波器组多载波系统误比特率性能优于传统基于块交织的滤波器组多载波系统。     

输送机中心轴线标定及测量精度分析

通过对带式输送机安装中心轴线标定方法进行理论分析,推导出边长和角度实测的精度相关公式,同时输送机的施工安装工艺对测量标定中心轴线提出了较高的要求,为我们提出了在实际工作中的具体做法和应注意的几个问题。     

天然气输送支干线生产管理探讨

天然气输送管线安全运行面临风险,本文主要对天然气输送管线生产管理进行探讨。     

浅谈测量员如何更好更快地提高业务水平

测量作为服务于国民经济建设的重要行业，随着传统测绘技术向数字化测绘技术转化，它表现出复杂性及多样性，当我们面对一项新的测量任务时，除了传统学习模式之外，我们该如何更好地提高自身地业务水平呢？本文结合作者工作经验论述了上述问题，为测量同行提供一些建议及指导。     

A number‐of‐modes reference rule for density estimation under multimodality

We consider kernel density estimation for univariate distributions. The question of interest is as follows: given that the data analyst has some background knowledge on the modality of the data (for instance, ‘data of this type are usually bimodal’), what is the adequate bandwidth to choose? We answer this question by extending Silverman's idea of ‘normal‐reference’ to that of ‘reference to a Gaussian mixture’. The concept is illustrated in the light of real data examples.