Abstract

Pre‐exposure prophylaxis (PrEP) to prevent HIV enables female sex workers (FSWs) to protect themselves from HIV without relying on clients using condoms. Yet, because PrEP reduces HIV risk, financial incentives to not use condoms may lead to risk compensation: reductions in condom use and/or increases in commercial sex, and may reduce the price of unprotected sex.

We integrated market forces into a dynamic HIV transmission model to assess how risk compensation could change the impact of PrEP among FSWs and clients. We parameterise how sexual behavior may change with PrEP use among FSWs using stated preference data combined with economic theory. Our projections suggest the impact of PrEP is sensitive to risk compensatory behaviors driven by changes in the economics of sex work. Condom substitution could reduce the impact of PrEP on HIV incidence by 55%, while increases in the frequency of commercial sex to counter decreases in the price charged for unprotected sex among PrEP users could entirely mitigate the impact of PrEP. Accounting for competition between PrEP users and nonusers exacerbates this further.

Intervention studies need to determine how HIV prevention products may change the economics of sex work and provision of unprotected sex to enable a better understanding of their impact.

Abstract

Do gays earn less than other men because they are less competitive? Do lesbians earn more than other women because they are more competitive? To answer these questions, we conduct an experiment on a Dutch online survey panel to measure the competitive preferences of gay, lesbian and straight panel members. We find that gay men compete less than straight men, while lesbians compete as much as straight women. Linking our experimental measure of competitiveness to earnings and education data, we find that competitiveness predicts earnings and education levels and that differences in competitive preferences can partially explain the gay earnings penalty but not the lesbian premium.

Abstract

Marriage has declined since 1960, with the drop being more significant for noncollege-educated individuals versus college-educated ones. Divorce has increased, more so for the noncollege-educated. Additionally, positive assortative mating has risen. Income inequality among households has also widened. A unified model of marriage, divorce, educational attainment, and married female labor-force participation is developed and estimated to fit the postwar US data. Two underlying driving forces are considered: technological progress in the household sector and shifts in the wage structure. The analysis emphasizes the joint role that educational attainment, married female labor-force participation, and marital structure play in determining income inequality.

Abstract

A growing number of papers theoretically study the effects of introducing a preference signaling mechanism. However, the empirical literature has had difficulty proving a basic tenet, namely that an agent has more success when the agent uses a signal. This paper provides evidence based on a field experiment in an online dating market. Participants are randomly endowed with two or eight “virtual roses” that a participant can use for free to signal special interest when asking for a date. Our results show that, by sending a rose, a person can substantially increase the chance of the offer being accepted, and this positive effect is neither because the rose attracts attention from recipients nor because the rose is associated with unobserved quality. Furthermore, we find evidence that roses increase the total number of dates, instead of crowding out offers without roses attached. Despite the positive effect of sending roses, a substantial fraction of participants do not fully utilize their endowment of roses and even those who exhaust their endowment on average do not properly use their roses to maximize their dating success.

Abstract

Pre‐exposure prophylaxis (PrEP) to prevent HIV enables female sex workers (FSWs) to protect themselves from HIV without relying on clients using condoms. Yet, because PrEP reduces HIV risk, financial incentives to not use condoms may lead to risk compensation: reductions in condom use and/or increases in commercial sex, and may reduce the price of unprotected sex.

We integrated market forces into a dynamic HIV transmission model to assess how risk compensation could change the impact of PrEP among FSWs and clients. We parameterise how sexual behavior may change with PrEP use among FSWs using stated preference data combined with economic theory. Our projections suggest the impact of PrEP is sensitive to risk compensatory behaviors driven by changes in the economics of sex work. Condom substitution could reduce the impact of PrEP on HIV incidence by 55%, while increases in the frequency of commercial sex to counter decreases in the price charged for unprotected sex among PrEP users could entirely mitigate the impact of PrEP. Accounting for competition between PrEP users and nonusers exacerbates this further.

Intervention studies need to determine how HIV prevention products may change the economics of sex work and provision of unprotected sex to enable a better understanding of their impact.

Abstract

Do gays earn less than other men because they are less competitive? Do lesbians earn more than other women because they are more competitive? To answer these questions, we conduct an experiment on a Dutch online survey panel to measure the competitive preferences of gay, lesbian and straight panel members. We find that gay men compete less than straight men, while lesbians compete as much as straight women. Linking our experimental measure of competitiveness to earnings and education data, we find that competitiveness predicts earnings and education levels and that differences in competitive preferences can partially explain the gay earnings penalty but not the lesbian premium.

Abstract

Marriage has declined since 1960, with the drop being more significant for noncollege-educated individuals versus college-educated ones. Divorce has increased, more so for the noncollege-educated. Additionally, positive assortative mating has risen. Income inequality among households has also widened. A unified model of marriage, divorce, educational attainment, and married female labor-force participation is developed and estimated to fit the postwar US data. Two underlying driving forces are considered: technological progress in the household sector and shifts in the wage structure. The analysis emphasizes the joint role that educational attainment, married female labor-force participation, and marital structure play in determining income inequality.

Abstract

A growing number of papers theoretically study the effects of introducing a preference signaling mechanism. However, the empirical literature has had difficulty proving a basic tenet, namely that an agent has more success when the agent uses a signal. This paper provides evidence based on a field experiment in an online dating market. Participants are randomly endowed with two or eight “virtual roses” that a participant can use for free to signal special interest when asking for a date. Our results show that, by sending a rose, a person can substantially increase the chance of the offer being accepted, and this positive effect is neither because the rose attracts attention from recipients nor because the rose is associated with unobserved quality. Furthermore, we find evidence that roses increase the total number of dates, instead of crowding out offers without roses attached. Despite the positive effect of sending roses, a substantial fraction of participants do not fully utilize their endowment of roses and even those who exhaust their endowment on average do not properly use their roses to maximize their dating success.

Abstract

In less than a decade, the internet went from being a series of loosely connected networks used by universities and the military to the powerful commercial engine it is today. This talk first describes how many of the key innovations made this possible. It will then discuss how mainstream service providers that had traditionally been leaders in the old-market economy became threatened by innovations from industry outsiders who saw economic opportunities where others didn’t – and how these mainstream firms had no choice but to innovate themselves. New models were tried: some succeeded, some failed. Commercial markets turned innovations into valuable products and services as the Internet evolved in those markets. New business processes had to be created from scratch as a network originally intended for research and military defense had to deal with network interconnectivity, the needs of commercial users, and a host of challenges with implementing innovative new services.

Abstract

The surge of interest in cryptocurrencies has been accompanied by a proliferation of fraud. This paper examines pump and dump schemes. The recent explosion of nearly 2,000 cryptocurrencies in an unregulated environment has expanded the scope for abuse. We quantify the scope of cryptocurrency pump and dump schemes on Discord and Telegram, two popular group-messaging platforms. We joined all relevant Telegram and Discord groups/channels and identified thousands of different pumps. Our findings provide the first measure of the scope of such pumps and empirically document important properties of this ecosystem.

Abstract

Digitization has led to a large number of new creative products, straining the capacity of professional critics and consumers to identify the best products. Yet, the digitization of retailing has also delivered new crowd-based sources of pre-purchase information. We compare the relative impacts of professional critics and crowd-based Amazon star ratings on consumer welfare in book publishing. Using various fixed effects and discontinuity-based empirical strategies, we find that both types of pre-purchase information significantly affect purchasing behavior. We use these causal estimates to calibrate structural demand models for measuring their welfare impacts. The aggregate effect of the existence of star ratings on consumer surplus is, in our baseline estimates, more than ten times the effect of traditional review outlets. Crowd-based information now accounts for the vast majority of pre-purchase information, but the absolute effects of professional reviews have not declined over time.

Abstract

A model is provided whereby a monopolist firm chooses to price its product at zero. This outcome is shown to be driven by the assumption of „free disposal“ alongside selection markets (where prices impact on a firm’s costs). Free disposal creates a mass point of consumers whose utility from the product is zero. When costs are negative, the paper shows that a zero price equilibrium can emerge. The paper shows that this outcome can be socially optimal and that, while a move from monopoly to competition can result in a negative price equilibrium, this can be welfare reducing. The conclusion is that zero can be a „special zone“ with respect to policy analysis such as in antitrust.

Abstract

Die Erforschung von Intelligenz und Rationalität ist eng miteinander verwoben. Herbert Simon, Wirtschaftsnobelpreisträger und ein Begründer der modernen Wissenschaft der Künstlichen Intelligenz, erklärte
bereits vor Jahrzehnten die Wirtschaftswissenschaft zu einer „Wissenschaft vom Künstlichen“.

Die Spieltheorie zeigt uns, welchen Strategien rationale Spieler folgen. Doch hat man es mit realen Menschen zu tun, so ändert sich, was als intelligent und rational bezeichnet werden kann. Der Vortrag illustriert anhand zahlreicher Beispiele, wie wirtschaftswissenschaftliche Vorstellungen der Rationalität und computerwissenschaftliche Ansätze der Künstlichen Intelligenz sich gegenseitig bei der Suche nach der perfekten Strategie in einer irrationalen Welt befruchten. Die Forschung birgt großartige Chancen und gewaltige Herausforderungen.