The value of a good reputation online: an application to art auctions

Using a unique dataset of art auctions on eBay, we conduct an empirical analysis of the value of a seller’s online reputation. Several aspects distinguish our work from most existing research. We analyze a heterogeneous panel data consisting of a large number of observations over a large period of time, including significant variation in reputation across and within sellers. The panel structure of our dataset allows us to employ fixed effects techniques to control for observed and unobserved differences across auctions. Our results point to a highly significant, and sizable, impact of a negative reputation on the behavior of market participants and on market outcomes. Negative feedback is associated with a significant reduction in the number of bidders and a reduction in the probability of sale; negative feedback is also associated with a significant reduction in sale price. Consistent with previous research, the impact of additional positive feedback on market outcomes for the seasoned sellers in our sample is not statistically significant.     

Correction to: A Critical Review of Students’ and Teachers’ Understandings of Nature of Science

Science & Education - The original article unfortunately contains incorrect presentation of Tables 1, 3, 4, 5 and 6.     

Student–teacher closeness and conflict in students with and without special educational needs

Teachers play a key role in creating effective conditions for students to succeed in school. The quality of student–teacher relationships is consistently associated with social, emotional, behavioural and academic adjustment, and this is even more relevant for students with special educational needs (SEN), considering these students’ emotional, social and learning vulnerabilities. This study aimed to examine the associations between students’ externalising and internalising behaviour, social skills and academic performance, and teachers’ perceptions of conflict and closeness in their relationships with students with and without SEN. Data regarding 360 students in Year 3, Year 5 and Year 7 (169 students with SEN) were collected. Teachers (n = 74) reported on the student–teacher relationship and students’ social skills, behaviour problems and academic performance. Special education teachers (n = 38) provided information regarding the diagnosis and profile of functioning of students with SEN. Results showed that teachers’ reports of students’ social skills and externalising problems were the strongest predictors of closeness and conflict. Internalising problems and SEN status also predicted decreased closeness, despite smaller effects. Taken together, findings support the importance of professional development opportunities focusing on facilitating teachers’ relationships with students with perceived challenging behaviour.     

A simple relation between the Leimkuhler curve and the mean residual life

In this paper, a simple relation between the Leimkuhler curve and the mean residual life is established. The result is illustrated with several models commonly used in informetrics, such as exponential, Pareto and lognormal. Finally, relationships with some other reliability concepts are also presented.     

The impact of explanatory factors on a bidimensional model of transparency in Spanish local government

The aim of this paper is to analyse the transparency provided by local public managers and to determine whether this disclosure is limited to the minimum quantity permissible (in accordance with Agency Theory) or whether a maximum amount of information is supplied (following Legitimacy Theory). To do so, we present a Bidimensional Transparency Index (BTI), developed as an instrument for measuring the provision of information (i.e. e-disclosure), which contains two components, breadth and depth, to reflect the pattern of behaviour observed. The results obtained show that on average local managers disclose information corresponding to 60% of the indicators considered, but that only 52% of these indicators of transparency present a moderate or considerable depth of content. These findings reflect a pattern of limited information disclosure, with incomplete information. In addition, our study shows that explanatory factors have an asymmetric impact on the components of the BTI.     

Eccentric flywheel post-activation potentiation influences swimming start performance kinetics

This study aimed to assess the effects of post-activation potentiation in the strength related variables of a kick start. Thirteen competitive swimmers performed three kick starts after a standardized warm up (denoted USUAL) and another after inducing post-activation through five isotonic repetitions on an eccentric flywheel (denoted PAP). A T-test was used to quantify differences between USUAL and PAP warm up. The best trial of each subject achieved by natural conditions (denoted PEAK) was compared with data obtained after PAP. An instrumented starting block with independent triaxial force plates, collected the strength variables related with the impulse at take off. Improvements in the vertical components of force were observed after PAP compared with USUAL, meanwhile no differences were detected on the horizontal components of it. The velocity at take off was higher after PAP compared with USUAL (4.32 ± 0.88 vs 3.93 ± 0.60 m*s-1; p = 0.02). No differences in force or velocity were detected comparing PAP with PEAK (4.13 ± 0.62 m*s-1, p = 0.11). The PAP warm-up increased vertical force and it was transferred to a higher resultant velocity at take-off. This improvement would equal the best result possible obtained in natural conditions after some trials.     

Grading in Portuguese secondary school physical education: assessment parameters,gender differences and associations with academic achievement

ABSTRACT

Background: Assessment is crucial for the quality of teaching and learning in physical education (PE). Currently little is known about the students’ level of achievement in PE and about the parameters used for calculating the PE grades. Although there is evidence that boys are more active outside school than girls and participate more in organized sports, few studies have examined possible differences between genders in PE achievement. Furthermore, despite the current interest in the relationship between motor competencies and cognitive functioning, limited research has examined if PE grades are associated with academic achievement.

Purpose: Considering the lack of information on the current level of students’ success in PE, the main aim of this study is to examine the PE grades of Portuguese students in secondary school. Specifically, this study analysis the level of students’ achievement in PE, the relation of PE grades with other school subjects’ grades, compares the PE grades between boys and girls, and presents the PE summative assessment parameters used in schools.

Method: Participants were 1936 students (57% girls) from the 10th, 11th and 12th grades (16.8?±?1.3 years old) attending eleven Portuguese secondary schools. Information was gathered on their grades in PE and in the other school subjects at the end of the school year. Information on the specific assessment parameters used in each school was also collected.

Results: The average grades in PE were 14.9?±?2.3 points (20-point scale). Only ～1% of students with a final PE grade had a negative performance (<10 points). PE grades were relatively higher than in most of the other school-subjects and for most students (68.7%) the PE classification raised their overall average grade. The level of correlation between grades in PE and in other school subjects was statistically significant (r's?=?.13 to .29, p?<?.05) although lower than that between grades in the other school subjects (r's?=?.44 to .84, p?<?.01). There were significant differences between girls’ and boys’ grades in PE (14.3?±?2.3 and 15.9?±?2.1 points, respectively). The school assessment parameters prioritize physical performance over participation and attitude.

Conclusion: The Portuguese students’ level of achievement in PE seems to be very satisfactory. However, as boys have higher grades than girls it is urgent to find appropriate strategies to tackle this problem. The associations found between PE grades and academic achievement could have relevant repercussions considering the current debate about the status of PE and about the relationship between motor and cognitive competencies. It is also relevant that the schools’ summative assessment parameters are based mainly on skill mastery and not on effort and participation. This study provided a brief glance into some aspects of the assessment of PE in Portugal and is it is desirable that future investigations examine the teacher's assessment practices.