The Price of Local Fairness in Multistage Selection

The rise of algorithmic decision making led to active researches on how to define and guarantee fairness, mostly focusing on one-shot decision making. In several important applications such as hiring, however, decisions are made in multiple stage with additional information at each stage. In such cases, fairness issues remain poorly understood. In this paper we study fairness in k-stage selection problems where additional features are observed at every stage. We first introduce two fairness notions, local (per stage) and global (final stage) fairness, that extend the classical fairness notions to the k-stage setting. We propose a simple model based on a probabilistic formulation and show that the locally and globally fair selections that maximize precision can be computed via a linear program. We then define the price of local fairness to measure the loss of precision induced by local constraints; and investigate theoretically and empirically this quantity. In particular, our experiments show that the price of local fairness is generally smaller when the sensitive attribute is observed at the first stage; but globally fair selections are more locally fair when the sensitive attribute is observed at the second stage – hence in both cases it is often possible to have a selection that has a small price of local fairness and is close to locally fair.

THE MOTIVES FOR ALCOHOL CONSUMPTION AND PREVENTION OF ITS ONSET IN MARIY EL REPUBLIC

Aim. To study the motives of student alcohol consumption in Mariy El republic and to create, according to the results, the relevant recommendations on prevention of alcoholization of studentship in educational institutions. Material and methods. Mass survey of learners (n=1209) of primary and higher educational institutions in Mariy El Republic. Multistage selection. At the first stage the selection was done from the educational institutions. At the second stage we selected focal student groups; inside the groups we performed total questioning. The proportion of the age and gender was followed. Survey was done with questionnaires. Results. Of participants 87,4% older than 14 y. already tasted alcohol. Of those 45% did it before their 15. 73,4% responders consume alcohol. Severe drunkenness experience periodically 48% of responders. 41,2% of those think that it is not bad to consume alcohol if not to overdrink. Students named a variety of motives for the first tasting of alcohol: interest, wish to have fun, wish to feel unusual, behaving as adults, wish to look more amateur, wish to relieve stress, to prove the identity in front of the same agers, to cure, to show a concern and respect, to celebrate an event. Current consumption motives can be classified as following: to move from the reality and life problems, to experience unusual feelings, to remove communication barriers, due to boredom and monotony, as a self-prove, to reach a specific emotional condition, as imitation of adults, to show social group, as a tradition, for treatment. Conclusion. Alcohol consumption is prevalent in students of Mariy El rebublic. There is a broad spectrum of motives for trying alcohol and continuing of consumption, that should be prevented by relevant preventive activities.