Level Of Measurement Precision Research Articles

Rotation Local Solutions in Multidimensional Item Response Theory Models

We conducted an extensive Monte Carlo study of factor-rotation local solutions (LS) in multidimensional, two-parameter logistic (M2PL) item response models. In this study, we simulated more than 19,200 data sets that were drawn from 96 model conditions and performed more than 7.6 million rotations to examine the influence of (a) slope parameter sizes, (b) number of indicators per factor (trait), (c) probabilities of cross-loadings, (d) factor correlation sizes, (e) model approximation error, and (f) sample sizes on the local solution rates of the oblimin and (oblique) geomin rotation algorithms. To accommodate these design variables, we extended the standard M2PL model to include correlated major factors and uncorrelated minor factors (to represent model error). Our results showed that both rotation methods converged to LS under some conditions with geomin producing the highest local solution rates across many models. Our results also showed that, for identical item response patterns, rotation LS can produce different latent trait estimates with different levels of measurement precision (as indexed by the conditional standard error of measurement). Follow-up analyses revealed that when rotation algorithms converged to multiple solutions, quantitative indices of structural fit, such as numerical measures of simple structure, will often misidentify the rotation that is closest in mean-squared error to the factor pattern (or item-slope pattern) of the data-generating model.

The Extreme Stellar-signals Project. III. Combining Solar Data from HARPS, HARPS-N, EXPRES, and NEID

We present an analysis of Sun-as-a-star observations from four different high-resolution, stabilized spectrographs—HARPS, HARPS-N, EXPRES, and NEID. With simultaneous observations of the Sun from four different instruments, we are able to gain insight into the radial velocity precision and accuracy delivered by each of these instruments and isolate instrumental systematics that differ from true astrophysical signals. With solar observations, we can completely characterize the expected Doppler shift contributed by orbiting Solar System bodies and remove them. This results in a data set with measured velocity variations that purely trace flows on the solar surface. Direct comparisons of the radial velocities measured by each instrument show remarkable agreement with residual intraday scatter of only 15–30 cm s−1. This shows that current ultra-stabilized instruments have broken through to a new level of measurement precision that reveals stellar variability with high fidelity and detail. We end by discussing how radial velocities from different instruments can be combined to provide powerful leverage for testing techniques to mitigate stellar signals.

Thermodynamic Principle for Quantum Metrology.

The heat dissipation in quantum metrology represents not only an unavoidable problem towards practical applications of quantum sensing devices but also a fundamental relationship between thermodynamics and quantum metrology. However, a general thermodynamic principle which governs the rule of energy consumption in quantum metrology, similar to Landauer's principle for heat dissipation in computations, has remained elusive. Here, we establish such a physical principle for energy consumption in order to achieve a certain level of measurement precision in quantum metrology, and show that it is intrinsically determined by the erasure of quantum Fisher information. The principle provides a powerful tool to investigate the advantage of quantum resources, not only in measurement precision but also in energy efficiency. It also serves as a bridge between thermodynamics and various fundamental physical concepts related in quantum physics and quantum information theory.

Measuring functioning and disability using household surveys: metric properties of the brief version of the WHO and World Bank model disability survey

BackgroundThe Model Disability Survey (MDS) is the current standard recommended by WHO to collect functioning and disability data. Answering calls from countries requesting a version to be implemented as a module that could be integrated into existing surveys and be used for monitoring disability trends and for data disaggregation, WHO developed the brief MDS. The objectives of this paper are to evaluate the metric properties of the disability metrics generated with the Brief MDS and the precision of the Brief MDS in comparison with the full MDS.ResultsThe partial credit model, a unidimensional model for polytomous data from the Rasch family, was applied to evaluate psychometric properties using data from national MDS implementations in Chile (N = 12,265) and in Sri Lanka (N = 3000). The Brief MDS generates valid metrics for measuring disability, from the perspectives of capacity and performance, thereby achieving good levels of measurement precision in comparison with its full counterpart.ConclusionGiven the scarcity of valid functioning and disability modules for household surveys, the Brief MDS represents a milestone in disability measurement. The Brief MDS is currently used by countries to monitor disability trends over time, which is especially important to evaluate the impact of health policies and public health interventions, to disaggregate indicators of the Sustainable Development Goals, and to monitor the implementation of the UN Convention on the Rights of Persons with Disabilities (CRPD).

Assessing person-centred care: An item response theory approach.

Given recent advances in psychometric assessment, there is a need for assessment studies using modern test theory in the field of person-centred care, mainly due to the dominant use of analytical strategies based on classical test theory. The main objective of the present study was thus to examine whether selected items from commonly used instruments of person-centred care were able to differentiate between respondents with a reasonably even level of measurement precision across different regions of the construct range using item response theory (IRT). A Swedish sample of care staff in elderly care (N=1342) completed a survey including a selection of items from three previously validated measures of person-centred care. All questionnaire items were submitted to IRT analyses to examine the extent to which the items produced information on the underlying construct. The items exhibited different levels of information. However, in general, for those items exhibiting some information, the pattern of information across the trait range was similar for most of them, that is, the items discriminated better in the lower levels of person-centredness. Item response theory analyses are instrumental in creating shorter measurement instruments that may perform nearly as well as the original longer instruments. Given time and other resource constraints in questionnaire administration, there is a gain in only including the most informative items which efficiently and evenly tap the underlying construct along its entire range and in the context of person-centred care assessment this study was an initial step towards this goal. Thus, a set of ten items with satisfactory levels of psychometric quality, that is relatively high information levels across a relatively broad range of the underlying construct, is proposed.

How useful is each item in the Sport Spectator Identification Scale?: an item response theory analysis

PurposeThe purpose of this study is to evaluate the psychometric properties of each item in the Sport Spectator Identification Scale (SSIS) (Wann and Branscombe, 1993) using the item response theory (IRT) and to provide evidence for modifications in the scale.Design/methodology/approachA total of 635 spectators of US professional sports responded to the seven-item SSIS on an eight-point semantic differential scale. The general partial credit model was fitted to the data.FindingsThe results revealed that four items (Items 1, 2, 3 and 5) provide a relatively high amount of information, whereas three items (Items 4, 6 and 7) provide a low amount of information, indicating different levels of measurement precision among the items. Furthermore, the results showed that some low-level response options were rarely selected by participants, indicating that it may not be necessary to include response options as many as eight within each item.Originality/valueUnlike previous studies examining the psychometric properties of the SSIS as a whole, the present study provides information about the usefulness of each item of the SSIS in measuring individuals' team identification. Based on the findings, the authors identified some issues with the three problematic items, including the wording of the items and the link between the question and the target construct. The authors make several suggestions for researchers and practitioners in improving individual item quality and in making informed decisions when using the SSIS in the future.

A delayed gating approach for interference-free ratio-based phosphor thermometry

Accurate surface temperature measurements present vast difficulties in numerous technical applications, especially when imaging fast temperature changes. One example is spray-induced surface cooling, where temperature variations occur on the sub-millisecond timescale. Phosphor thermometry relies on changes in the photoluminescence properties (typically the lifetime or the emission spectrum) of phosphor materials for temperature determination. For temperature imaging in situations where short measurement durations are critical such as on fast moving objects or short and intense heat transfer events, the spectral method is preferred. However, in many situations, fluorescence signals over a broad spectral range originate from fuel, flame radicals, optical windows or even the chemical binder used to coat the phosphor material and may interfere with the measurements.In this work, we investigate a delay strategy for the spectral method that prevents interference from fluorescence sources by using a phosphor with a microsecond-range-lifetime. By applying a short delay (<1 µs), between excitation and detection, short-lived interfering fluorescence signals can be efficiently avoided. The temporal and spectral content of the fluorescence from the substrate, binder and fuel are investigated with a photomultiplier tube and a spectrometer respectively. The delayed gating strategy is then implemented for temperature imaging of the wetted side of a spray impinged surface with a tin-doped phosphor, (Sr,Mg)3(PO4)2:Sn2+; selected for its suitable lifetime (26 µs @ 300 K) and high temperature sensitivity. Calibration measurements for coated surfaces show that by avoiding fluorescence from the binder, the temperature sensitivity is improved from 0.3% K−1 to 0.8% K−1 at 293 K. Furthermore the calibration curve repeatability between two similar coatings is enhanced. Finally, temperature measurements of the cooling induced by a fluorescing impinging gasoline spray was successfully performed with this strategy owing the same level of measurement precision (0.5 K) as with a non-fluorescing fuel (n-hexane UV grade).

Computerized adaptive testing with decision regression trees: an alternative to item response theory for quality of life measurement in multiple sclerosis.

BackgroundThe aim of this study was to propose an alternative approach to item response theory (IRT) in the development of computerized adaptive testing (CAT) in quality of life (QoL) for patients with multiple sclerosis (MS). This approach relied on decision regression trees (DRTs). A comparison with IRT was undertaken based on precision and validity properties.Materials and methodsDRT- and IRT-based CATs were applied on items from a unidi-mensional item bank measuring QoL related to mental health in MS. The DRT-based approach consisted of CAT simulations based on a minsplit parameter that defines the minimal size of nodes in a tree. The IRT-based approach consisted of CAT simulations based on a specified level of measurement precision. The best CAT simulation showed the lowest number of items and the best levels of precision. Validity of the CAT was examined using sociodemographic, clinical and QoL data.ResultsCAT simulations were performed using the responses of 1,992 MS patients. The DRT-based CAT algorithm with minsplit = 10 was the most satisfactory model, superior to the best IRT-based CAT algorithm. This CAT administered an average of nine items and showed satisfactory precision indicators (R = 0.98, root mean square error [RMSE] = 0.18). The DRT-based CAT showed convergent validity as its score correlated significantly with other QoL scores and showed satisfactory discriminant validity.ConclusionWe presented a new adaptive testing algorithm based on DRT, which has equivalent level of performance to IRT-based approach. The use of DRT is a natural and intuitive way to develop CAT, and this approach may be an alternative to IRT.

Digitally Controlled AC Current Measurement and Protection Techniques

Abstract This paper describes a cost effective AC current measurement method that avoids complex AC to DC current measurements by converting an amplified and rectified AC voltage drop across a shunt resistor to a duty cycle of a PWM signal. The current measurement chain output is fed into a microcontroller unit (MCU) and into a short circuit protection block that inhibits AC load drivers in case of overcurrent or short circuit events, overriding the state set by the MCU control algorithm. The authors present a mathematical model, simulations and a practical evaluation of custom-developed circuits that are capable to reach a convincing level of measurement precision. By counting a given number of consecutive AC periods, the effect of inrush current generated by inductive AC loads is filtered. The proposed solution allows inrush currents up to 3A, fitting the consumption range of AC control elements met in household application circuits, such as relays or solenoid valves.

A Comparison of Unidimensionality and Measurement Precision of the Narcissistic Personality Inventory and the Narcissistic Admiration and Rivalry Questionnaire.

The current study compares the closeness to unidimensionality (CU) and measurement precision (MP) of the Narcissistic Personality Inventory (NPI)-with either a pairwise forced-choice or 5-point Likert-type scale response format-to the Narcissistic Admiration and Rivalry Questionnaire (NARQ). Minimum rank factor analysis and item information curves from item response models were utilized. The results mainly confirmed our expectations that NPI subscales are lower in CU and MP compared with NARQ subscales when the NPI was administered with its traditional forced-choice response format. When the NPI was administered with a 5-point Likert-type scale response format, the NPI subscale Leadership/Authority and NPI Grandiose Exhibitionism showed similarly high levels of CU and MP as the two NARQ subscales. While the NPI subscale Entitlement/Exploitativeness had a higher CU than the NARQ subscales it showed considerably lower levels of MP.

Extending the measurement of the latent traits in the Multidimensional Personality Questionnaire

If personality traits are truly dimensional, our measures will assess standing on those dimensions best if items tap their full ranges at relatively even intervals. This level of measurement precision has not generally been examined for common personality measures, but item response theory (IRT) models offer powerful tools for doing so. The frequency of skewed score distributions suggests that it could be informative. We report results of such analysis in the Multidimensional Personality Questionnaire (MPQ), among the most psychometrically robust measures of “normal” range personality. They indicated substantial but different gaps in item coverage in each of the 11 primary scales. We wrote 10 new items for each scale, intended to fill its particular gaps. We report the extent to which we succeeded and discuss implications for thinking of ‘abnormal’ personality as lying at the extremes of ‘normal’ personality. What, for example, does it mean to be ‘a little’ aggressive?.

The multi-dimensional model of Māori identity and cultural engagement: Item response theory analysis of scale properties.

We argue that there is a need for culture-specific measures of identity that delineate the factors that most make sense for specific cultural groups. One such measure, recently developed specifically for Māori peoples, is the Multi-Dimensional Model of Māori Identity and Cultural Engagement (MMM-ICE). Māori are the indigenous peoples of New Zealand. The MMM-ICE is a 6-factor measure that assesses the following aspects of identity and cultural engagement as Māori: (a) group membership evaluation, (b) socio-political consciousness, (c) cultural efficacy and active identity engagement, (d) spirituality, (e) interdependent self-concept, and (f) authenticity beliefs. This article examines the scale properties of the MMM-ICE using item response theory (IRT) analysis in a sample of 492 Māori. The MMM-ICE subscales showed reasonably even levels of measurement precision across the latent trait range. Analysis of age (cohort) effects further indicated that most aspects of Māori identification tended to be higher among older Māori, and these cohort effects were similar for both men and women. This study provides novel support for the reliability and measurement precision of the MMM-ICE. The study also provides a first step in exploring change and stability in Māori identity across the life span. A copy of the scale, along with recommendations for scale scoring, is included.

The maximum priority index method for severely constrained item selection in computerized adaptive testing

This paper introduces a new heuristic approach, the maximum priority index (MPI) method, for severely constrained item selection in computerized adaptive testing. Our simulation study shows that it is able to accommodate various non-statistical constraints simultaneously, such as content balancing, exposure control, answer key balancing, and so on. Compared with the weighted deviation modelling method, it leads to fewer constraint violations and better exposure control while maintaining the same level of measurement precision.

Precision and accuracy of joint space width measurements of the medial compartment of the knee using standardized MTP semi-flexed radiographs

Objective: To quantify the precision and accuracy of measurements of joint space width (JSW) and joint space narrowing (JSN) from the medial tibiofemoral compartment of knee radiographs using a simple and easily adaptable protocol. Methods: Radiographs of a caliper (a surrogate for JSW) were obtained to determine the precision limits of the system under ideal conditions. Bilateral knee radiographs from 10 healthy volunteers were obtained at three different times using the metatarsophalangeal (MTP) semi-flexed view posterior–anterior position without fluoroscopy. A backlit digitizing tablet and three manual methods were used to measure JSW and analyses of precision were performed. The accuracy of measuring change in JSW (a measure of JSN) was estimated from radiographs of cadaver knees that were placed in a servo-hydraulic device that moved the femur relative to the tibia through known intervals. Results: Radiographic measurements of the caliper inter-blade distance were comparable to the resolution limits of the backlit digitizing tablet (0.025 mm). Repeated radiography of healthy subject knees produced JSW standard deviation (SD) measurements of 0.08 mm by the median SD method, and 0.11 mm by repeated measures analysis. The accuracy of JSN measurements in the cadaver knees as a mean difference from the known reference value was 0.09 mm. Conclusion: The results indicate a high level of precision in measurements of JSW from MTP semi-flexed view knee radiographs of normal volunteers. Reproducibility was attained through careful subject positioning without fluoroscopy and the use of a backlit digitizing tablet. From the cadaver study we can predict that greater than 0.13 mm of measured JSN represents actual or true change in JSN. This radiographic technique can be used as a primary measure for early knee osteoarthritis (OA) when cartilage thickness is decreasing and limited bony remodeling has occurred.

Evaluation of the number of laser-Doppler measurements in assessing regional diaphragmatic microcirculation.

As regional diaphragmatic microvascular blood flow varies widely, the aim in this study was to estimate the number of repeated measurements, obtained by Laser-Doppler flowmetry (LDF), required to achieve a standard level of precision. In 40 urethane-anesthetized Sprague-Dawley rats, computer-aided LDF scanning coupled with a microscope generated diaphragmatic blood flow (Qdi) ranging between 94 and 944 mV with the frequency histogram displaying non-Gaussian distributions. A sampling technique was used to assess the number of measuring sites required for valid estimates of the regional diaphragmatic microvascular flow. From a total of 1,000 Qdi values, random samples of sizes between 5 and 100 were repeatedly drawn to estimate the variability of median flow. Our data shows that the 95th percentile decreased gradually, from a +30% error at n = 5 down to +20% at n = 15-20, remained between +20 and +15% up to n = 35, and reached +10% at n = 50. Moreover, by expressing the precision level of measurements as the length of a 95% confidence interval (beta), a linear relationship between beta values obtained either by the sampling method or repeated measures analysis of variance can be shown (r = 0.902, p < 0.001); beta values by either method were within +/-20% error of the mean values at sample sizes above n = 15. It is therefore recommended that for microscope-guided LDF scanning in the assessment of the distribution of diaphragmatic microvascular blood flow, at least 15 repeated measurements should be done to reach an acceptable standard level of precision. However, facing with clinical situations where 'blind' LDF scanning inevitably includes measurements over large vessels, the minimal sample sizes required to represent tissue perfusion demand further exploration.

Ensuring the quality, reliability and precision of measurement processes through traceability

Inadequate measurement capability can place a heavy burden of implicit costs on manufacturers – even drive them out of business. It can have serious consequences for stakeholders in industry, commerce or science. High‐technology manufacturing must ensure a high level of precision in measurements, often to as much as a millionth of an inch. In seeking such high levels of precision, measurement laboratories often use traceability as a key precision criterion. Two comprehensive sets of measurements made over time by high‐precision laboratories on gauge blocks are used to explore the scope of traceability in ensuring high‐precision measurements. Significant differences were found between the high‐precision primary laboratories traceable to the National Institute of Standards and Technology in the USA. Explores general implications of such between‐laboratory differences and makes recommendations for secondary laboratories and stakeholders in dimensional metrology seeking to ensure a high level of precision in their measurements.