Non-response biases in surveys of schoolchildren: the case of the English Programme for International Student Assessment (PISA) samples

We analyse response patterns to an important survey of schoolchildren, exploiting rich auxiliary information on respondents' and non-respondents' cognitive ability that is correlated both with response and the learning achievement that the survey aims to measure. The survey is the Programme for International Student Assessment (PISA), which sets response thresholds in an attempt to control the quality of data. We analyse the case of England for 2000, when response rates were deemed sufficiently high by the organizers of the survey to publish the results, and 2003, when response rates were a little lower and deemed of sufficient concern for the results not to be published. We construct weights that account for the pattern of non-response by using two methods: propensity scores and the generalized regression estimator. There is clear evidence of biases, but there is no indication that the slightly higher response rates in 2000 were associated with higher quality data. This underlines the danger of using response rate thresholds as a guide to quality of data

Socioeconomic gradients in children's cognitive skills: are cross-country comparisons robust to who reports family background

The international surveys of pupil achievement—Programme for International Student Assessment (PISA), Trends in International Mathematics and Science Study, and Progress in International Reading Literacy Study (PIRLS)—have been widely used to compare socio-economic gradients in children’s cognitive abilities across countries. Socio-economic status is typically measured drawing on children’s reports of family or home characteristics rather than information provided by their parents. There is a well-established literature based on other survey sources on the measurement error that may result from child reports. But there has been little work on the implications for the estimation of socioeconomic gradients in test scores in the international surveys, and especially their variation across countries. In this article, we use the PISA and PIRLS data sets to investigate the consistency of parent and child reports of three common socio-economic indicators (father’s occupation, parental education, and the number of books in the family home) across a selection of OECD countries. Our results suggest that children’s reports of their father’s occupation provide a reliable basis on which to base comparisons across countries in socio-economic gradients in reading test scores. The same is not true, however, for children’s reports of the number of books in the home—a measure commonly used—while results for parental education are rather mixed

Teachers in England’s secondary schools: evidence from TALIS 2013

En ligne sur https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/322910/RR302_-_TALIS_report_NC.pdfThe Teaching and Learning International Survey (TALIS), led by the Organisation for Economic Cooperation and Development (OECD), provides new information on the views and practices of lower secondary teachers and their headteachers and on how these vary across countries. England participated in TALIS for the first time in 2013 the only part of the UK to do so. The survey included over 30 other countries or parts of countries.This national report for England is published simultaneously with the OECD's first international report on TALIS 2013. It complements the OECD's report by (i)providing a more focused comparison of England with other countries and (ii) analysing differences within England across school and teacher characteristics. International comparisons of England made in the national report include contrasts with a group of nine countries or parts of countries with high performing educational systems: Japan, Korea, Singapore, Finland, Estonia, The Netherlands, Flanders (Belgium), Alberta (Canada) and Australia. The report reveals that teacher views and practices often vary widely among these high performers. Analysis of differences within England is enhanced by using the answers to additional TALIS questions not asked in other countries and by linking the survey data to contextual information for each school such as its Ofsted rating and the percentage of pupils receiving free school meals

Pacing Behavior and Tactical Positioning in 500- and 1000-m Short-Track Speed Skating

Purpose: To explore pacing behavior and tactical positioning during the shorter 500- and 1000-m short-track competitions. Methods: Lap times and intermediate rankings of elite 500- and 1000-m short-track-skating competitors were collected over the 2012–13 season. First, lap times were analyzed using a MANOVA, and for each lap, differences between sex, race type, final ranking, and stage of competition were determined. Second, Kendall tau-b correlations were used to assess relationships between intermediate and final rankings. In addition, intermediate rankings of the winner of each race were examined. Results: Top-placed athletes appeared faster than bottom-placed athletes in every lap in the 500-m, while in the 1000-m no differences were found until the final 4 laps (P < .05). Correlations between intermediate and final rankings were already high at the beginning stages of the 50-m (lap 1: r = .59) but not for the 1000-m (lap 1: r = .21). Conclusions: Although 500- and 1000-m short-track races are both relatively short, fundamental differences in pacing behavior and tactical positioning were found. A fast-start strategy seems to be optimal for 500-m races, while the crucial segment in 1000-m races seems to be from the 6th lap to the finish line (ie, after ± 650 m). These findings provide evidence to suggest that athletes balance between choosing an energetically optimal profile and the tactical and positional benefits that play a role when riding against an opponent, as well as contributing to developing novel insights in exploring athletic behavior when racing against opponents

Even Between-Lap Pacing Despite High Within-Lap Variation During Mountain Biking

Purpose: Given the paucity of research on pacing strategies during competitive events, this study examined changes in dynamic high-resolution performance parameters to analyze pacing profiles during a multiple-lap mountain-bike race over variable terrain. Methods: A global-positioning-system (GPS) unit (Garmin, Edge 305, USA) recorded velocity (m/s), distance (m), elevation (m), and heart rate at 1 Hz from 6 mountain-bike riders (mean ± SD age = 27.2 ± 5.0 y, stature = 176.8 ± 8.1 cm, mass = 76.3 ± 11.7 kg, VO2max = 55.1 ± 6.0 mL · kg–1 . min–1) competing in a multilap race. Lap-by-lap (interlap) pacing was analyzed using a 1-way ANOVA for mean time and mean velocity. Velocity data were averaged every 100 m and plotted against race distance and elevation to observe the presence of intralap variation. Results: There was no significant difference in lap times (P = .99) or lap velocity (P = .65) across the 5 laps. Within each lap, a high degree of oscillation in velocity was observed, which broadly reflected changes in terrain, but high-resolution data demonstrated additional nonmonotonic variation not related to terrain. Conclusion: Participants adopted an even pace strategy across the 5 laps despite rapid adjustments in velocity during each lap. While topographical and technical variations of the course accounted for some of the variability in velocity, the additional rapid adjustments in velocity may be associated with dynamic regulation of self-paced exercise

Risk perception influences athletic pacing strategy.

PURPOSE: The objective of this study is to examine risk taking and risk perception associations with perceived exertion, pacing, and performance in athletes. METHODS: Two experiments were conducted in which risk perception was assessed using the domain-specific risk taking (DOSPERT) scale in 20 novice cyclists (experiment 1) and 32 experienced ultramarathon runners (experiment 2). In experiment 1, participants predicted their pace and then performed a 5-km maximum effort cycling time trial on a calibrated Kingcycle mounted bicycle. Split times and perceived exertion were recorded every kilometer. In experiment 2, each participant predicted their split times before running a 100-km ultramarathon. Split times and perceived exertion were recorded at seven checkpoints. In both experiments, higher and lower risk perception groups were created using median split of DOSPERT scores. RESULTS: In experiment 1, pace during the first kilometer was faster among lower risk perceivers compared with higher risk perceivers (t(18) = 2.0, P = 0.03) and faster among higher risk takers compared with lower risk takers (t(18) = 2.2, P = 0.02). Actual pace was slower than predicted pace during the first kilometer in both the higher risk perceivers (t(9) = -4.2, P = 0.001) and lower risk perceivers (t(9) = -1.8, P = 0.049). In experiment 2, pace during the first 36 km was faster among lower risk perceivers compared with higher risk perceivers (t(16) = 2.0, P = 0.03). Irrespective of risk perception group, actual pace was slower than predicted pace during the first 18 km (t(16) = 8.9, P < 0.001) and from 18 to 36 km (t(16) = 4.0, P < 0.001). In both experiments, there was no difference in performance between higher and lower risk perception groups. CONCLUSIONS: Initial pace is associated with an individual's perception of risk, with low perceptions of risk being associated with a faster starting pace. Large differences between predicted and actual pace suggest that the performance template lacks accuracy, perhaps indicating greater reliance on momentary pacing decisions rather than preplanned strategy.This is the author accepted manuscript. The final version is available from Wolters Kluwer via http://dx.doi.org/10.1249/MSS.000000000000050

P2Y12-dependent modulation of ADP-evoked calcium responses in human monocytes

The Gi-coupled, ADP-activated P2Y12 receptor is well-characterised as playing a key role in platelet activation via crosstalk with P2Y1. A crucial aspect of P2Y12-P2Y1 crosstalk in platelets involves ADP-induced intracellular calcium (Ca2+) mobilisation, however there is limited knowledge on the role of P2Y12 in ADP-evoked Ca2+ responses in other blood cells. Here, we investigate the expression of P2Y12 in human monocytes and the contribution of P2Y12 in THP-1 ADP-evoked Ca2+ responses. RT-PCR analysis showed that all ADP-binding P2Y receptors were expressed in THP-1 monocytes at the mRNA level, with P2Y12 expressed in CD14+ primary monocytes. P2Y12 protein was found to be expressed in THP-1 cells, using immunocytochemistry. ADP-evoked Ca2+ responses in fura-2-loaded THP-1 cells were completely abolished by a sarco/endoplasmic reticulum Ca2+-ATPase inhibitor, and by a phospholipase C inhibitor, indicating that these Ca2+ responses are mediated through GPCRs. Ca2+ responses induced by ADP were significantly reduced by the P2Y12 inhibitors ticagrelor and PSB-0739 and by the P2Y6 antagonist MRS2578, but not by P2Y1 or P2Y13 inhibitors. Using P2Y6-overexpressing astrocytomas, ticagrelor was found to be selective for P2Y12 over P2Y6 at the concentrations used here, although PSB-0739 was not. ADP-induced Ca2+ responses were significantly decreased in THP-1 cells with siRNA-mediated P2Y12 knockdown. Pertussis toxin-mediated Gi inhibition caused a significant reduction in ADP-induced Ca2+ responses, as did the PI3K inhibitor LY294002. Use of the adenylate cyclase inhibitor SQ22536 had no effect on sole ADP-evoked Ca2+ responses, but caused significant recovery of Ca2+ responses inhibited by P2Y12 antagonists. The results from this study suggest that Ca2+ responses evoked by ADP in THP-1 cells are dependent on both P2Y12 and P2Y6 activation, with P2Y12 positively modulating Gq-coupled P2Y6-mediated Ca2+ responses via adenylate cyclase inhibition and PI3K activation. Overall, this investigation reveals a new role for P2Y12 in non-platelet Ca2+ responses, and contributes to our understanding of how monocytes function in health and disease

Pacing Ability in Elite Runners with Intellectual Impairment

Purpose. To understand how athletes invest their energy over a race, differences in pacing ability between athletes with and without intellectual impairment (II) were explored using a novel field test. Methods. Well-trained runners (n=67) participated in this study, including 34 runners with II (age = 24.4 +/- 4.5 years; IQ = 63.1 +/- 7.7) and 33 runners without II (age = 31.4 +/- 11.2 years). The ability to perform at a pre-planned submaximal pace was assessed. Two 400m running trials were performed on an athletics track, with an individually standardized velocity. In the first trial, the speed was imposed by auditory signals given in 20m-40m intervals, in combination with coach-feedback during the initial 200m. The participant was instructed to maintain this velocity without any feedback during the final 200m. In trial 2, no coach-feedback was permitted. Results. Repeated measures analyses revealed a significant between-groups effect. II-runners deviated more from the target time than runners without II. The significant trial x group interaction effect (F = 4.15, p<.05) revealed that the ability to self-regulate the pace during the final 200m improved for runners without II (Trial 1: 1.7 +/- 1.0s, Trial 2: 0.9 +/-0.8s) whereas the II-runners deviated even more in Trial 2 (4.4 +/- 4.3s), than in Trial 1 (3.2 +/- 3.9s). Conclusion. Our findings support the assumption that intellectual capacity is involved in pacing. It is demonstrated that II-runners have difficulties maintaining a preplanned submaximal velocity, and this study contributes to understanding problems II-exercisers might experience when exercising. With this field test, we can assess the impact of II on pacing and performance in individual athletes which will lead to a fair Paralympic classification-procedure

PISA 2015: how big is the ‘mode effect’ and what has been done about it?

The Programme for International Student Assessment (PISA) is an important cross-national study of 15-year-olds’ academic knowledge and skills. Educationalists and public policymakers eagerly await the tri-annual results, with particular interest in whether their country has moved up or slid down the international rankings, as compared to earlier rounds. In 2015 a major change was implemented in PISA, with the introduction of computer-based assessment. This has the potential to reduce comparability of PISA test scores across countries and over time. We investigate this issue using PISA 2015 field trial data for three countries: Germany, Sweden, and Ireland. We show how, if left unaccounted for, the change to computer-based testing could limit the comparability of PISA test scores. We then describe the methodology the study organisers have used to account for such mode effects. Our key conclusion is that although the adjustment made is unlikely to overcome all the potential challenges of switching to computer-based tests, it represents an improvement over the alternative of making no adjustment at all

Physiological and Psychological Effects of Deception on Pacing Strategy and Performance: A Review

The aim of an optimal pacing strategy during exercise is to enhance performance whilst ensuring physiological limits are not surpassed, which has been shown to result in a metabolic reserve at the end of the exercise. There has been debate surrounding the theoretical models that have been proposed to explain how pace is regulated, with more recent research investigating a central control of exercise regulation. Deception has recently emerged as a common, practical approach to manipulate key variables during exercise. There are a number of ways in which deception interventions have been designed, each intending to gain particular insights into pacing behaviour and performance. Deception methodologies can be conceptualised according to a number of dimensions such as deception timing (prior to or during exercise), presentation frequency (blind, discontinuous or continuous) and type of deception (performance, biofeedback or environmental feedback). However, research evidence on the effects of deception has been perplexing and the use of complex designs and varied methodologies makes it difficult to draw any definitive conclusions about how pacing strategy and performance are affected by deception. This review examines existing research in the area of deception and pacing strategies, and provides a critical appraisal of the different methodological approaches used to date. It is hoped that this analysis will inform the direction and methodology of future investigations in this area by addressing the mechanisms through which deception impacts upon performance and by elucidating the potential application of deception techniques in training and competitive settings