Background Although the need for whole blood is declining, so too are the number of first‐time and repeat blood donors. To develop new recruitment and retention strategies, therefore, we need to draw on as wide a variation in blood donor motivations as possible. The primary aim of this study is to draw on a large survey of donors to develop a broad, theoretically instantiated typology of donor motivations to identify new and less common, yet practically important, motivations that have not been previously reported. Study Design and Methods Using data from the UK Blood Donor Survey run by NHS Blood and Transplant/Public Health England Epidemiology Unit (N = 61 123 donors), we analyze fixed (N = 52 225) and free (N = 8867) responses to develop a more comprehensive typology of blood donor motivations based on theories from the biology, psychology, philosophy, economics, and sociology of altruism. Results We identified 54 motivations, including a number of newly identified motivations, for blood donations which we organized into 12 superordinate categories (eg, “inspiration via moral elevation,” “perceived social closeness,” and “fungibility of donations”). These are linked to intervention suggestions such as donating blood in memoriam or donating blood as an alternative to other charitable acts. Conclusion We present the most comprehensive account of blood donor motivations to‐date. This work also offers a structure for coding free‐text responses, developing motivational measures, and identifying tangible interventions. Thus, we feel that this is a valuable resource for blood donor researchers, marketers, and policy makers.

This article presents evidence on peer effects among U.S. agricultural workers. On average, we find that a 10% increase in peer productivity increases focal worker productivity by 2.8%. This effect is modified by the ability and gender of workers and peers. Exceptionally slow workers are least responsive to peers and have pronounced negative spillovers on the productivity of their coworkers—their presence decreases productivity by 2%. Male workers are more responsive to their peers than female workers—a 10% increase in peer productivity increases the productivity of men by 3% and women by 2.6%. Workers are also generally more responsive to peers of similar ability and gender. Workers increase their speed the most when in the presence of peers with abilities just above their own. Male workers are more responsive to male peers than female peers, and female workers are more responsive to female peers.

Labor markets can shape the impacts of global market developments and local sustainability policies on agricultural outcomes, including changes in production and land use. Yet local labor market outcomes, including agricultural employment, migration and wages, are often overlooked in Integrated Assessment Models (IAMs). The relevance of labor markets has become more important in recent decades, with evidence of diminished labor mobility in the United States and other developed countries. We use the SIMPLE-G (Simplified International Model of agricultural Prices, Land use, and the Environment) modeling framework to investigate the impacts of a global commodity price shock and a local sustainable groundwater use policy in the United States (US). SIMPLE-G is a multi-scale framework designed to allow for integration of economic and biophysical determinants of sustainability, using fine-scale geospatial data and parameters. We use this framework to compare the impacts of the two sets of shocks under two contrasting assumptions: perfect mobility of agricultural labor, as generally implicit in global IAMs, and relatively inelastic labor mobility (“sticky” agricultural labor supply response). We supplement the numerical simulations with analytical results from a stylized two-input model to provide further insights into the impacts of local and global shocks on agricultural labor, crop production and resource use. Findings illustrate the key role that labor mobility plays in shaping both local and global agricultural and environmental outcomes. In the perfect labor mobility scenario, the impact of a commodity price boom on crop production, employment and land-use is overestimated compared with the restricted labor mobility case. In the case of the groundwater sustainability policy, the perfect labor mobility scenario overestimates the reduction in crop production and employment in directly targeted grids as well as spillover effects that increase employment in other grids. For both shocks, impacts on agricultural wages are completely overlooked if we ignore rigidities in agricultural labor markets.

The labor supply response to agricultural wages is critical to the viability of crop production in high-income countries, which hire a largely foreign farm work force, as well as in low-income countries, where domestic workers move off the farm as the agricultural transformation unfolds. Modeling agricultural labor supply is more challenging than modeling the supply of other agricultural inputs or of labor to other sectors of the economy owing to unique features of agricultural production and farm labor markets. Data and econometric challenges abound, and estimates of agricultural labor supply elasticities are sparse. This review explains the importance and challenges of modeling farm labor supply and describes researchers’ efforts to address these challenges. It summarizes estimates of agricultural labor supply elasticities over the last 80 years, provides insights into variation in these estimates, identifies priority areas for future research, and reviews the most influential empirical work related to this important topic. Expected final online publication date for the Annual Review of Resource Economics, Volume 13 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.