Management Review Quarterly - Substantial efforts have contributed to overcome the scarcity of research on hidden champions. Nevertheless, literature has yet missed to compile a comprehensive... 相似文献
Non-parametric estimation of the survival function using observed failure time data depends on the underlying data generating mechanism, including the ways in which the data may be censored and/or truncated. For data arising from a single source or collected from a single cohort, a wide range of estimators have been proposed and compared in the literature. Often, however, it may be possible, and indeed advantageous, to combine and then analyse survival data that have been collected under different study designs. We review non-parametric survival analysis for data obtained by combining the most common types of cohort. We have two main goals: (i) to clarify the differences in the model assumptions and (ii) to provide a single lens through which some of the proposed estimators may be viewed. Our discussion is relevant to the meta-analysis of survival data obtained from different types of study, and to the modern era of electronic health records. 相似文献
Poverty remains a substantial threat in rural areas of many developing countries, and solving this problem requires an in-depth understanding of the income generating capacity that determines poverty. This paper examines the impact of agricultural commercialisation on the capability of rural households to accumulate and productively use assets and reduce structural and multidimensional poverty. A longitudinal dataset of around 2000 households with a total of 9781 observations from five rural surveys undertaken in the period 2008–2017 in Vietnam is used. Results from a fixed effects regression with an instrumental variable and a control function approach show that agricultural commercialisation has a positive effect on the accumulation of assets and reduces multidimensional and structural poverty over time. However, the effect is not homogeneous and is larger for households that are not mainly engaged in rice commercialisation. This suggests that commercialisation can be a path out of poverty, especially if policy makers move towards utilising other crops instead of rice. 相似文献
Benchmark replacement rates are a key parameter for retirement plans. Often, a pension level of around 70 per cent of net income during working life is considered as an adequate choice. However, this heuristic value is left unjustified, and data-based benchmarks are limited. In this paper, we propose to estimate a pension-level benchmark based on keeping the living standard achieved during working life constant after retirement. Applying parametric, semi-parametric and non-parametric estimation methods to data from the United States and Germany, we find that a net pension income of around 100 per cent of the last net working-life income, plus or minus 10 percentage points, is required to keep the living standard constant. However, we also find that the outcome of the exercise can depend on how ‘living standards’ are measured. 相似文献
Platforms use price parity clauses to prevent sellers setting lower prices when selling through other channels. They claim these restraints are needed so platforms have incentives to invest in providing search services—without them, consumers would search on the platform but then switch to buy in a cheaper channel. In a model incorporating these effects, we find that wide price parity clauses lead to excessive platform investment while narrow (or no) price parity clauses lead to insufficient platform investment. Taking these investment effects into account, wide price parity clauses lower consumer surplus but have ambiguous effects on total welfare. 相似文献
The “freemium” model for digital goods involves selling a base version of the product for free, and making premium product features available to users only on payment. The success of the model is predicated on the ability to profitably convert free users to paying ones. Price promotions (or “sales”) are often used in freemium to induce this conversion. However, the causal effect of exposing consumers to such inter-temporal price variation is unclear. While sales can generate beneficial short-run conversion, they may be harmful in the long-run if consumers inter-temporally substitute purchases to periods with low prices, or use them as signals of low product quality. These long-run concerns may be accentuated in freemium apps, where the base version is sold for free, so that sales form extreme price cuts on the overall product combination. We work with the seller of a free-to-play video game to randomize entering cohorts of users into treatment and control conditions in which promotions for in-game purchases are turned on or off. We observe complete user behavior for half a year, including purchases and consumption of in-game goods, which, in contrast to much of the extant literature, enables us to assess possible substitution over time in consumption directly. We find that conversion and revenue improve in the treatment group; and detect no evidence of harmful inter-temporal substitution or negative inferences about quality from exposure to price variation, suggesting that promotions are profitable. We conjecture that the zero price of the base product that makes its consumption virtually costless, combined with the complementarity between the base product and premium features can help explain this. To the extent that this holds across freemium contexts, the positive effects of promotions documented here may hold more generally.
International Journal of Technology and Design Education - K-12 Engineering Education has placed a lot of attention on students’ attitudes or predispositions towards science and technology.... 相似文献