Potential Sources Of Measurement Error Research Articles

A new instrument for interfacial dilational rheology.

We present a new design for an interfacial dilational rheometer that can generate oscillatory dilational strain on a planar air-liquid interface. The strain is generated by a pneumatic mechanism involving a deformable film, which forms a circular barrier that can contract or expand under different pressures. The interfacial stress is measured using a Wilhelmy rod. We carefully examine and demonstrate the effects of potential sources of measurement error, including inertia, drag, buoyancy, flow from the bulk phase, and surface waves. The design avoids mixed deformations present in other instruments and is currently capable of accurate measurements at frequencies up to ∼0.1Hz and dilational strains below 0.001, with potential for higher frequencies after further theoretical development. We demonstrate the integration of the interfacial dilational rheometer with a Langmuir trough by measuring the compression isotherm of an insoluble surfactant, stearic acid. Furthermore, we verify the capability of the interfacial dilational rheometer to perform frequency and amplitude sweeps and present the storage and loss moduli for a water-soluble surfactant, sodium dodecylbenzenesulfonate, at different concentrations.

Can Measurement Error Explain Slow Productivity Growth in Construction?

Of all major industries, construction is the only one to have registered negative average productivity growth since 1987. One might suspect measurement error to have biased growth downward since the deflators for this sector, which are used to translate nominal construction spending into the real quantity of structures, have risen much faster than those for other sectors. We find evidence of an upward bias in these deflators related to unobserved improvements in structure quality, but the magnitude is not large enough to alter the view that construction-sector productivity growth has been weak. We also find only small contributions from other potential sources of measurement error. We conclude that productivity growth may well have been quite low in construction, even if it has not been as low as implied by official statistics.

Number Preference as a Source of Measurement Error in the U.S. National Forest Inventory

Number preference, i.e., the human tendency to gravitate toward or away from specific numbers, is a potential source of measurement error in forest inventory. Identifying its presence is an important step to ensure unbiased results. This study evaluated U.S. national forest inventory data for number preference and identified factors that influence the proportion of tree cull volume, tree diameter, tree height, and seedling count observations ending with the digit zero or five (ED0,5) and seedling count observations that were multiples of four (M4). Two-sided hypothesis tests determined that ED0,5 occurred significantly more frequently than expected by chance for all metrics tested, though not in every inventory region of the country nor to the same degree. Consistently, tree-level ED0,5 was more likely when metrics were estimated visually rather than measured instrumentally. Logistic regression indicated that the effect of species class, species type, tree status, treetop status, and stem size on tree-level ED0,5 and the effect of plot-level water depth on seedling count ED0,5 also varied by region. Though the effect was small, findings suggest that some inventory regions may be employing an approved multiplicative shortcut that results in a greater-than-expected proportion of M4 observations among seedling counts.

Position of Correct Option and Distractors Impacts Responses to Multiple-Choice Items: Evidence From a National Test.

Even though the impact of the position of response options on answers to multiple-choice items has been investigated for decades, it remains debated. Research on this topic is inconclusive, perhaps because too few studies have obtained experimental data from large-sized samples in a real-world context and have manipulated the position of both correct response and distractors. Since multiple-choice tests' outcomes can be strikingly consequential and option position effects constitute a potential source of measurement error, these effects should be clarified. In this study, two experiments in which the position of correct response and distractors was carefully manipulated were performed within a Chilean national high-stakes standardized test, responded by 195,715 examinees. Results show small but clear and systematic effects of options position on examinees' responses in both experiments. They consistently indicate that a five-option item is slightly easier when the correct response is in A rather than E and when the most attractive distractor is after and far away from the correct response. They clarify and extend previous findings, showing that the appeal of all options is influenced by position. The existence and nature of a potential interference phenomenon between the options' processing are discussed, and implications for test development are considered.

Relative Performance of Business and Consumer Economic Expectations Across EU Countries

Survey designs that aim at international comparisons of economic expectations are complex. Question wording and response scales must be applicable across countries to provide policy makers with reliable information. Substantial progress on harmonization has been made by the EU in their member surveys. While forming expectations is a difficult task for anyone, business firms have been thought to have a distinct advantage over consumers. This paper investigates this presumed superiority by examining whether firms change their expectations in advance of households, and whether firms’ expectations provide more accurate forecasts than household expectations. The comparisons are based on monthly expectations data for the countries in the European Union. While linkages were often found to be bidirectional, the data more frequently found unidirectional linkages that went from households to firms for unemployment and GDP. For a modest number of countries, firms and households jointly contributed to forecast accuracy, but the sole impact of household data clearly dominated the comparable results for firms. The objective of this analysis was exploratory, with the goal to identify countries which lacked significant connections for a more detailed investigation of the potential sources of measurement errors.

The Effect of Psychological Distress on Measurement Invariance in Measures of Mental Wellbeing.

A growing literature supports the expansion of mental health assessment to include indicators of mental wellbeing; however, the concurrent use of measures of wellbeing and distress introduces potential sources of measurement error. The current study examines whether the mental health continuum short form is invariant to the level of participants’ psychological distress. Measurement invariance testing was conducted within an Australian population (n = 8406) who participated in an online survey. The depression anxiety stress scale was used to construct a non-distressed group (n = 6420) and a severe-distress group (n = 1968). Results showed that metric invariance was not observed, as item loadings on the latent variables were significantly different between the groups. This signifies that wellbeing items may be interpreted and valued differently by distressed and non-distressed individuals. Metric non-invariance indicates that total and subscale scores may not be equivalent, and caution is required when making comparisons between these groups.

Rapid growth of thoracic aortic aneurysm: Reality or myth?

ObjectivesThe American Association for Thoracic Surgery 2010 guidelines stipulate that rapid growth of the aorta (>3 mm/y) is an indication for prophylactic surgical intervention. Because of the many potential sources of error in aortic measurement (including measurement variability and comparison of noncorresponding segments), we explored whether rapid aortic growth was a reality or a falsehood. MethodsAmong 2781 patients with aortic disease who were treated over 3 decades, we examined aortic growth rate in 811 patients with at least 2 aortic images taken at least 2 years apart. We identified 42 ascending and 27 descending patients with putative rapid aortic growth. A team of experienced clinicians reread the source images. ResultsAmong the 42 ascending patients with putative rapid aortic growth, rapid growth was confirmed in 12 and refuted in 11 (19 images nonretrievable). Among the 27 descending patients, rapid growth was confirmed in 6 and refuted in 4 (17 images nonretrievable). We calculated lower, middle, and highest possible rapid growth rates by prorating positivity rates for nonretrievable scans. Lowest, middle, and highest possible rates of rapid growth were 2.7%, 4.7%, and 6.9% for ascending aorta, and 1.6%, 4.3%, and 7.3% for descending aneurysms, respectively. Middle rates are considered most accurately reflective. Of the patients with confirmed rapid growth, 3 of 4 inoperable patients succumbed to their aorta. Twenty-three patients underwent prompt surgery, with 22 survivors. For the rapidly growing aortas, operative, pathologic, and genetic findings are reported. ConclusionsAlthough not a falsehood, rapid growth is uncommon for the ascending and descending aorta. Many putative cases are reflective of measurement error. Attention to potential sources of measurement error is key. Video Abstract [Display omitted]

Methodological considerations on estimating medication adherence from self-report, electronic monitoring and electronic healthcare databases using the TEOS framework.

Measuring adherence to medication is complex due to the diversity of contexts in which medications are prescribed, dispensed and used. The Timelines-Events-Objectives-Sources (TEOS) framework outlined a process to operationalize adherence. We aimed to develop practical recommendations for quantification of medication adherence using self-report (SR), electronic monitoring (EM) and electronic healthcare databases (EHD) consistent with the TEOS framework for adherence operationalization. An adherence methodology working group of the International Society for Medication Adherence (ESPACOMP) analysed implications of the process of medication adherence for all data sources and discussed considerations specific to SR, EM and EHD regarding the information available on the prescribing, dispensing, recommended and actual use timelines, the four events relevant for distinguishing the adherence phases, the study objectives commonly addressed with each type of data, and the potential sources of measurement error and quality criteria applicable. Four key implications for medication adherence measurement are common to all data sources: adherence is a comparison between two series of events (recommended and actual use); it refers to one or more specific medication(s); it applies to regular repeated events coinciding with known recommended dosing; and it requires separate measurement of the three adherence phases for a complete picture of patients' adherence. We propose recommendations deriving from these statements, and aspects to be considered in study design when measuring adherence with SR, EM and EHD using the TEOS framework. The quality of medication adherence estimates is the result of several design choices that may optimize the data available.

Choice and consumption of animal or plant-based protein: Controlling experimentally and statistically for sensory stimulus aspects and food choice factors

Everyday consumer food choices are influenced by a variety of interacting biological, situational, economical, and psychological factors [1–4]. The choice between animal-based and plant-based protein has implications for overall and cause-specific mortality and cardiometabolic health (e.g. [5–9]). During laboratory experiments that are designed to better understand factors that influence protein choice specifically, controlling for the sensory aspects of stimuli, health information, consumers’ physical characteristics, and dietary preferences is crucial. To illustrate the point, if a choice task included two stimuli, brown rice with tofu and steak with fries for example, a variety of factors, such as visual appeal and hedonic attributes could influence protein choice and dilute the effect of the experimental manipulation. This article provides a template for a generic experiment to measure participant choice among salt-cured jerky protein sources (e.g. beef, salmon, soy, textured vegetable protein, turkey, tuna) and consumed amounts. Using jerky products as stimuli minimizes variance in visual appearance, texture, and nutritional values, therefore facilitating the attribution of the experimental factor(s). A list of methods to experimentally and/or statistically control for potential sources of measurement error is provided.•Consumer choice of animal vs. plant-based protein has implications for individual and environmental health.•The methods can be used to customize experiments in consumer behavior research, psychology, and nutrition sciences.•Food choice is influenced by a variety of factors; experimentally and/or statistically controlling for major sources of measurement error increases confidence in the effect of the manipulated variable.

Can They and Will They? Exploring Proxy Response of Sexual Orientation and Gender Identity in the Current Population Survey

AbstractWithin the United States Federal Statistical System, there has been interest in capturing sexual orientation (SO) and gender identity (GI), collectively known as SOGI, on surveys to allow researchers to estimate the size and distribution of sexual and gender minority populations. SOGI measurement in federal surveys may also help to identify disparities between people who identify as lesbian, gay, bisexual, and transgender (LGBT) and those who do not in domains such as health, crime, or employment. Although research has been conducted on best practices for SOGI measurement in surveys, it has largely been limited to examination of self-reports. Many federal surveys use proxy reports, when one person generally responds for all household members. This research used cognitive interviews and focus groups to explore proxy response to SOGI questions. We explored potential sources of measurement error in proxy responses to SOGI questions, including sensitivity, difficulty, as well as the willingness and ability of respondents to answer SOGI questions about other household members. We also conducted paired interviews with members of the same household to assess level of agreement for SOGI questions. Findings suggest that measuring SOGI by proxy may be feasible in federal large-scale, general population surveys.

Global inequality: How large is the effect of top incomes?

Abstract Despite the growing interest in global inequality, assessing inequality trends is a major challenge because individual data on income or consumption is not often available. Nevertheless, the periodic release of certain summary statistics of the income distribution has become increasingly common. Hence, grouped data in form of income shares have been conventionally used to construct inequality trends based on lower bound approximations of inequality measures. This approach introduces two potential sources of measurement error: first, these estimates are constructed under the assumption of equality of incomes within income shares; second, the highest income earners are not included in the household surveys from which grouped data is obtained. In this paper, we propose to deploy a flexible parametric model, which addresses these two issues in order to obtain a reliable representation of the income distribution and accurate estimates of inequality measures. This methodology is used to estimate the recent evolution of global interpersonal inequality from 1990 to 2015 and to examine the effect of survey under-coverage of top incomes on the level and direction of global inequality. Overall, we find that item non-response at the top of the distribution substantially biases global inequality estimates, but, more importantly, it might also affect the direction of the trends.

Importance of over-reading ambulatory ECG-based microvolt T-wave alternans to eliminate three main sources of measurement error.

Ambulatory electrocardiogram (ECG)-based microvolt T-wave alternans values measured by the modified moving average method (MMA-TWA) can be disrupted by T-wave changes that mimic true repolarization alternans. We investigated potential sources of measurement error by studying 19 healthy subjects (12 men; median age, 25) free of known heart disease with 36-month follow-up to establish freedom from significant arrhythmia or syncope. All participants underwent 24-hr continuous 12-lead ECG monitoring. Causes of automated MMA-TWA ≥42µV episodes were classified based on visual inspection. A total of 2,189 episodes of automated MMA-TWA episodes ≥42µV were observed in all subjects (peak MMA-TWA: median, 94μV; interquartile range, 81-112μV). All episodes included one or more beats with T-wave deformation which lacked "repeating ABAB pattern" and therefore were identified as TWA measurement error. Causes of such error were categorized as: (a) artifact [72.6% (1,589/2,189), observed in 19 (100%) subjects], more frequently in limb than precordial leads; (b) T-wave changes due to changes in heart/body position [25.5% (559/2,189), observed in 14 (73.7%) subjects], frequently observed in leads V1-2; and (c) postextrasystolic T-wave changes [1.9% (41/2,189), observed in 2 (10.5%) subjects]. Relying only on automated MMA-TWA values obtained during ambulatory ECG monitoring can lead to incorrect measurement of TWA. Our findings offer the potential to reduce false-positive TWA results and to achieve more accurate detection of true repolarization alternans.

Measuring Trust in Medical Researchers: Adding Insights from Cognitive Interviews to Examine Agree-Disagree and Construct-Specific Survey Questions.

While scales measuring subjective constructs historically rely on agree-disagree (AD) questions, recent research demonstrates that construct-specific (CS) questions clarify underlying response dimensions that AD questions leave implicit and CS questions often yield higher measures of data quality. Given acknowledged issues with AD questions and certain established advantages of CS items, the evidence for the superiority of CS questions is more mixed than one might expect. We build on previous investigations by using cognitive interviewing to deepen understanding of AD and CS response processing and potential sources of measurement error. We randomized 64 participants to receive an AD or CS version of a scale measuring trust in medical researchers. We examine several indicators of data quality and cognitive response processing including: reliability, concurrent validity, recency, response latencies, and indicators of response processing difficulties (e.g., uncodable answers). Overall, results indicate reliability is higher for the AD scale, neither scale is more valid, and the CS scale is more susceptible to recency effects for certain questions. Results for response latencies and behavioral indicators provide evidence that the CS questions promote deeper processing. Qualitative analysis reveals five sources of difficulties with response processing that shed light on under-examined reasons why AD and CS questions can produce different results, with CS not always yielding higher measures of data quality than AD.

Reader response: ELAPSS score for prediction of risk of growth of unruptured intracranial aneurysms.

In the article by Backes et al.,1 the primary outcome was defined as greater than 1 mm growth as measured at local sites. The use of this cutoff was not referenced and a 1 mm change could be subject to potential measurement error. Furthermore, if different imaging modalities in one patient (magnetic resonance angiography vs CT angiography) were used to measure growth, their results could also lead to measurement error. An additional source of error and bias is if the physician carrying out the measurement was aware of the prior size. In that instance, the interpreting physician may judge an aneurysm that is larger to be more likely to grow, thereby biasing measurement. The potential sources of measurement error and bias may affect the results; it would be helpful to know if there was a blinded central reading center.

Measurement uncertainty associated with chromatic confocal profilometry for 3D surface texture characterization of natural human enamel

ObjectiveTo investigate the measurement performance of a chromatic confocal profilometer for quantification of surface texture of natural human enamel in vitro. MethodsContributions to the measurement uncertainty from all potential sources of measurement error using a chromatic confocal profilometer and surface metrology software were quantified using a series of surface metrology calibration artifacts and pre-worn enamel samples. The 3D surface texture analysis protocol was optimized across 0.04mm2 of natural and unpolished enamel undergoing dietary acid erosion (pH 3.2, titratable acidity 41.3mmolOH/L). ResultsFlatness deviations due to the x, y stage mechanical movement were the major contribution to the measurement uncertainty; with maximum Sz flatness errors of 0.49μm. Whereas measurement noise; non-linearity’s in x, y, z and enamel sample dimensional instability contributed minimal errors. The measurement errors were propagated into an uncertainty budget following a Type B uncertainty evaluation in order to calculate the Standard Combined Uncertainty (uc), which was ±0.28μm. Statistically significant increases in the median (IQR) roughness (Sa) of the polished samples occurred after 15 (+0.17 (0.13)μm), 30 (+0.12 (0.09)μm) and 45 (+0.18 (0.15)μm) min of erosion (P<0.001 vs. baseline). In contrast, natural unpolished enamel samples revealed a statistically significant decrease in Sa roughness of −0.14 (0.34) μm only after 45min erosion (P<0.05s vs. baseline). SignificanceThe main contribution to measurement uncertainty using chromatic confocal profilometry was from flatness deviations however by optimizing measurement protocols the profilometer successfully characterized surface texture changes in enamel from erosive wear in vitro.

A Reliability Generalization Study of the Political Skill Inventory

Measures of political skill have been shown to be significant predictors of job performance across a variety of occupations and have consistently been related to positive work-related behaviors and outcomes. A reliability generalization study was conducted on the Political Skill Inventory (PSI), currently the most frequently utilized measuring instrument for assessing the construct of political skill, to determine the weighted mean internal consistency reliability estimate of the PSI and its four dimensions across samples while also examining the effect of six potential sources of measurement error that may impact the internal consistency reliability of the PSI and its four dimensions. Across the samples that reported a reliability estimate for the Ferris et al. 18-item PSI measure, the weighted mean reliability coefficient alpha of the PSI was .89 (k = 77, N = 15,987) and that for the six-item measure of the PSI was .81 (k = 11, N = 2,123). Potential sources of measurement error variance that could impac...

The effect of data availability in measuring fund managers’ after‐tax alphas

AbstractWe examine potential sources of measurement error when evaluating the after‐tax performance of fund managers based on periodic snapshots of their holdings alone, compared with when daily transactions data are also available. To do this, we compare portfolio return estimates based on imputed trades from monthly, quarterly and semi‐annual snapshots with estimates that also incorporate daily trades for a sample of active institutional equity portfolios. This method allows us to directly measure the contribution of interim trading before tax, while more accurately estimating the tax effects associated with turnover through observing actual trade prices. Further, availability of both trade and holdings data permits the identification of how contributions and tax effects arise from income and capital gains sources, as well as how they vary across investment styles and market conditions.

Determinants of Wealth Fluctuation: Changes in Hard-To-Measure Economic Variables in a Panel Study.

Measuring fluctuation in families' economic conditions is the raison d'être of household panel studies. Accordingly, a particularly challenging critique is that extreme fluctuation in measured economic characteristics might indicate compounding measurement error rather than actual changes in families' economic wellbeing. In this article, we address this claim by moving beyond the assumption that particularly large fluctuation in economic conditions might be too large to be realistic. Instead, we examine predictors of large fluctuation, capturing sources related to actual socio-economic changes as well as potential sources of measurement error. Using the Panel Study of Income Dynamics, we study between-wave changes in a dimension of economic wellbeing that is especially hard to measure, namely, net worth as an indicator of total family wealth. Our results demonstrate that even very large between-wave changes in net worth can be attributed to actual socio-economic and demographic processes. We do, however, also identify a potential source of measurement error that contributes to large wealth fluctuation, namely, the treatment of incomplete information, presenting a pervasive challenge for any longitudinal survey that includes questions on economic assets. Our results point to ways for improving wealth variables both in the data collection process (e.g., by measuring active savings) and in data processing (e.g., by improving imputation algorithms).

Electrochemical Measurements in In Situ TEM Experiments

Potential sources of measurement error in electroanalytical analyses performed in-situ within a transmission electron microscope (TEM) are reported. Some relevant aspects of experimental set-up that impact noise are identified. The possibility of ground loops and recommendations that minimize them are presented. Offsets in the measured open circuit potential of working electrodes caused by the presence of the electron beam in TEM are demonstrated and discussed. This work also highlights the possibility of erroneous potential measurements when the electrode area exposed to electrolyte is significantly larger than the beam illumination area. General design criteria are proposed to assist in future electrochemical cell designs to mitigate electrochemical measurement artifacts inside a TEM.

New Estimates on Educational Attainment Using a Continuous Approach (1970–2010)

Summary In this paper we introduce a new set of estimates on educational attainment and inequality measures of education for 142 countries over the period 1970–2010. Most of the previous attempts to measure educational attainment have treated education as a categorical variable, whose mean is computed as a weighted average of the official duration of each cycle and attainment rates, thus omitting differences in educational achievement within levels of education. This aggregation into different groups may result in a loss of information, introducing, therefore, a potential source of measurement error. We explore here a more nuanced alternative to estimate educational attainment, which considers the continuous nature of education. This “continuous approach” allows us to impose more plausible assumptions about the distribution of years of schooling within each level of education, and to take into account the right censoring of the data in the estimation, thus leading to more accurate estimates of educational attainment and education inequality. These improved estimates may help to better understand the role of education on different aspects of development.