INDUCING OVERCONFIDENCE

In this study, I present a theory which explains how the influence of others may generate overconfidence. The argument is built on the idea that the more help an agent receives when performing a task, the less informative the score on that task will be relative to the agent's ability to perform it. If an agent is confident, he tends to benefit from more cooperation opportunities simply because he is likely to be perceived as being more skilled. As a result, he remains confident because the future signals he will observe will contain very little information regarding his ability. On the contrary, if the agent is not confident, he will receive more informative scores, which will help him learn his true ability faster. (JEL D81, D83, D84)     

Insights from the Evaluation of Past Local Area Population Forecasts

Local area population forecasts have a wide variety of uses in the public and private sectors. But not enough is known about the errors of such forecasts, particularly over the longer term (20 years or more). Understanding past errors is valuable for both forecast producers and users. This paper (i) evaluates the forecast accuracy of past local area population forecasts published by Australian State and Territory Governments over the last 30 years and (ii) illustrates the ways in which past error distributions can be employed to quantify the uncertainty of current forecasts. Population forecasts from the past 30 years were sourced from State and Territory Governments. Estimated resident populations to which the projections were compared were created for the geographical regions of the past projections. The key features of past forecast error patterns are described. Forecast errors mostly confirm earlier findings with regard to the relationship between error and length of projection horizon and population size. The paper then introduces the concept of a forecast ‘shelf life’, which indicates how far into the future a forecast is likely to remain reliable. It also illustrates how past error distributions can be used to create empirical prediction intervals for current forecasts. These two complementary measures provide a simple way of communicating the likely magnitude of error that can be expected with current local area population forecasts.     

Ice pack induced perineal analgesia after spontaneous vaginal birth: Randomized controlled trial

Background

Ice-pack is widely used for alleviating postpartum perineal pain sustained after birth related perineal trauma. However, it lacks robust evidence on timing and frequency of applications, to ensure the effective and safe use of this therapy.

A global count of the extreme poor in 2012: data issues,methodology and initial results

The 2014 release of a new set of purchasing power parity (PPP) conversion factors (PPPs) for 2011 has prompted a revision of the World Bank’s international poverty line. In revising the line, we have sought to minimize changes to the real purchasing power of the earlier $1.25 line (in 2005 PPPs), so as to preserve the integrity of the goalposts for international targets such as the Sustainable Development Goals (SDGs) and the World Bank’s twin goals – which were set with respect to that line. In particular, the new line was obtained by inflating the same fifteen national poverty lines – originally used by Ravallion et al. (World Bank Econ. Rev. 23(2): 163–184 2009) to construct the $1.25 line – to 2011 prices in local currency units, and then converting them to US dollars using 2011 PPP conversion factors. With a small approximation, this procedure yields a new international poverty line of $1.90 per person per day. In combination with other changes described in the paper, this revision leads to relatively small changes in global poverty incidence for 2011: from 14.5 % using the old method to 14.1 % using the new method. In 2012, the new reference year for the global count, we find 12.7 % of the world’s population, or 897 million people, are living in extreme poverty. There are changes in the regional composition of poverty, but they are also relatively small. This paper documents methodological decisions taken in the process of updating both the poverty line and the consumption and income distributions at the country level, including issues of inter-temporal and spatial price adjustments. It also describes various caveats and limitations of the approach taken.     

Proposal for an integrative methodology to development the ergonomic program

This paper collects the experience for both, academic and professional practice, and deal with the stages and level of involvement from different elements in the organization. The work is focused in some kind of concentric cycles, the very outside circle is formed by those that interact with ergonomic process in a year period, and the inner cycles are those that acts in a daily or weekly intervention. The success of the program still depending on the good will of the managers, but any action directed on benefit of the people at work, enable the moral as well as indicators for health and safety.     

Thermal comfort and personal protective equipment (PPE)

Personal Protective Equipment (PPE) is considered the last preferred solution to an Occupational Safety Health (OSH) system. Brazilian OSH legislation assumes and requires PPE usage to neutralize the possibility of pesticide contamination. This study examines the inadequacy of the PPE used in a tomato crop, particularly from the standpoint of thermal comfort. This study made observations regarding heart rate and body temperature in a controlled environment using a treadmill (with and without PPE) of 12 volunteers; and during the process of rural labor (at rest and in normal work routine) of 2 actual rural workers. Comparing the results of the treadmill test (with and without PPE) which tried to reproduce the same level of effort and environmental conditions of the actual rural work, this study demonstrated that PPE makes thermoregulation harder and tympanic temperature reaches higher values with the same level of effort. Moreover, body temperature increases quickly: with PPE it took 15 minutes to raise 1°C in body temperature, compared to 40 minutes without PPE. The results of this study indicated that the use inadequate PPE might pose thermoregulation risk to rural workers.     

Ergonomics and the inclusion of people with disabilities in a Brazilian workplace

The customization of a secretary workstation at a drama school was the objective of this case study. The investigation involved a 25-year-old illiterate woman with intellectual disabilities and low vision that had been been attending, for over 12 years, a state school for people with disabilities. The customization process, operationalized after a diagnosis was made, focused on environmental rearrangements, with the purpose of meeting the physical and social demands of the workstation. The results of this research are configured in an ergonomic analysis of work associated with an inventory of social skills, applied to people living directly with the participant. Preliminary evaluations indicated the degree of adjustment of labor demands to the personal characteristics of the participant in the customized job.     

Ergonomics in projects of oil platforms in a change context

The context of oil platform design is changing in order to increase competitiveness and be prepared for difficult operations, mainly in fields more distant from the coast, like pre-salt. The currently preceding context is marked by projects guidelines designed to reduce projects and operation costs, including an important reducing in the number of people on board. The main objective of this research is to verify and discuss if the experience of use in platforms designed in a previous context, in which the people on board is practically twice, can contribute and/or can be transferred to new projects. From the ergonomic intervention in the design of two oil platform, with the work of team on board investigated on previous projects as reference, it was possible analyze if the previous use is still applicable to new projects. As a result, about 90% of the recommendations based on use are applicable to the current context. The restrictions on the transfer or operational experience are mainly related to the time of entry of ergonomics in the design process, the subsequent transformations costs and the advance of the execution phase started with the detailed design.     

Dynamic factor structure of team performances in Liga MX

Team performance of the Mexican Football League (Liga MX), measured as the percentage of the total points obtained during each short tournament, is analyzed using Dynamic Factor Models (DFMs). The estimation of the common components is carried out with Principal Components and the stochastic nature of the DFM is studied through Panel Analysis of Non-stationarity in Idiosyncratic and Common Components. The results reveal that there are two common factors, one being possibly non-stationary. These factors show an interesting dynamic behavior in the league and allow to split the teams into two groups, namely, top competitors and emerging or relegated teams. Some discussion is given in this direction.     

Bivariate Birnbaum-Saunders accelerated lifetime model: estimation and diagnostic analysis

In this paper, we discuss the bivariate Birnbaum-Saunders accelerated lifetime model, in which we have modeled the dependence structure of bivariate survival data through the use of frailty models. Specifically, we propose the bivariate model Birnbaum-Saunders with the following frailty distributions: gamma, positive stable and logarithmic series. We present a study of inference and diagnostic analysis for the proposed model, more concisely, are proposed a diagnostic analysis based in local influence and residual analysis to assess the fit model, as well as, to detect influential observations. In this regard, we derived the normal curvatures of local influence under different perturbation schemes and we performed some simulation studies for assessing the potential of residuals to detect misspecification in the systematic component, the presence in the stochastic component of the model and to detect outliers. Finally, we apply the methodology studied to real data set from recurrence in times of infections of 38 kidney patients using a portable dialysis machine, we analyzed these data considering independence within the pairs and using the bivariate Birnbaum-Saunders accelerated lifetime model, so that we could make a comparison and verify the importance of modeling dependence within the times of infection associated with the same patient.