Trgi kot orodje za napovedovanje

Trgi kot orodje za napovedovanje: primer slovenske volilne borz

The Regression Tournament: A Novel Approach to Prediction Model Assessment

Standard methods to assess the statistical quality of econometric models implicitly assume there is only one person in the world, namely the forecaster with her model(s), and that there exists an objective and independent reality to which the model predictions may be compared. However, on many occasions, the reality with which we compare our predictions and in which we take our actions is co-determined and changed constantly by actions taken by other actors based on their own models. We propose a new method, called a regression tournament, to assess the utility of forecasting models and taking these interactions into account. We present an empirical case of betting on Australian Rules Football matches where the most accurate predictive model does not yield the highest betting return, or, in our terms, does not win a regression tournament.

Umanjuje li zaposlenost studenata njihov akademski uspjeh? Slučaj Slovenije

The article examines features of student work in Slovenia and estimates the impact of the scope of student work on successful completion of an academic year. After intense debate about merits and perils of student work in Slovenia in recent years, which was based on scarce survey data, this is the first study to statistically test the assertion that student work negatively affects academic performance. Different variants of the probit model are estimated using a rich sample of data for 1,890 undergraduate students in tertiary education working through one of the largest student employment services in Slovenia in the period 2005-2008. The results support a common finding from previous empirical studies for other countries that student employment has a (small) adverse impact on academic performance only when hours of paid work exceed some threshold level, in our case around 18 hours per week. The study also reveals only a weak seasonal component in student work, meaning that students work relatively evenly throughout the year. It also points to the lack of connection between the types of work performed by students and their fields of study.Rad analizira obilježja studentskog rada u Sloveniji i procjenjuje učinak opsega studenstkog rada na uspješno savladavanje akademske godine. Nakon žustre rasprave o prednostima i nedostacima studentskog rada u Sloveniji koja se vodila tijekom posljednjih nekoliko godina, a koja se temeljila na malo rezultata istraživanja, ovo je prvi rad kojim se statistički provjerava tvrdnja da studentski rad negativno utječe na njihov akademski uspjeh. Različite varijante probit modela testiraju se koristeći velik broj podataka za reprezentativni uzorak od 1890 studenata diplomskih studija koji su u razdoblju od 2005. do 2008.godine radili posredovanjem jedne od najvećih agencija za zapošljavanje studenata u Sloveniji. Rezultati potkrepljuju spoznaju koja je zajednička prethodnim empirijskim istraživanjima iz drugih zemalja, a to je da zaposlenost studenata ima (malen) negativni učinak na njihov akademski uspjeh samo kada sati njihova plaćenog rada premašuju određenu razinu, koja je u našem slučaju 18 sati tjedno. Istraživanje isto tako pokazuje vrlo slabu sezonsku komponentu u studentskom radu, što znači da student rade u relativno podjednakom opsegu tijekom cijele godine. Isto tako, rad ukazuje na nepovezanost između vrste rada koje student obavljaju i njihovih područja studija