Marginal Rate Of Substitution Research Articles

Preferences for adjuvant immunotherapy in patients with resected stage III melanoma: A discrete choice experiment.

9558 Background: Adjuvant immunotherapy has revolutionized the management of resectable melanoma, substantially reducing the risk of recurrence but at the risk of immune-related adverse events (AE). This study aimed to quantify patients' preferences for adjuvant immunotherapy, the influence of varying levels of key attributes, and baseline characteristics associated with preferences. Methods: We performed a discrete choice experiment (DCE), including patients with resected stage III melanoma considering or having received adjuvant immunotherapy. Patients chose between twelve randomly presented choice tasks of two alternative options (adjuvant immunotherapy versus observation without adjuvant immunotherapy). The two options varied across two-three levels of six attributes: chance of 3-year melanoma recurrence, mild, permanent, or fatal AE, drug regimen, and out-of-pocket costs. We calculated the marginal rate of substitution (MRS, how much an individual was willing to trade one attribute for preferred levels of another) and willingness-to-pay (WTP, maximum price to trade their preferred attributes) per year. Results: One hundred and sixteen patients completed the DCE. Patients chose adjuvant immunotherapy over observation without adjuvant immunotherapy in 70% of choice tasks. Patients preferred adjuvant immunotherapy with reduced probabilities of recurrence (OR 0.76, 95% CI 0.70-0.83, p<0.001), fatal AE (OR 0.60, 95% CI 0.44-0.80, p=0.006), permanent AE (OR 0.94, 95% CI 0.89-0.99, p=0.046), and lowered out-of-pocket costs, for those with lower incomes (OR 0.63, 95% CI 0.47-0.85, p=0.003) and higher incomes (OR 0.84, 95% CI 0.15-4.86, p=0.064). Patients accepted an increase in their chance of mild AE from 1% to 37% (OR 2.06, 95% CI 1.13-3.78, p=0.019) in return for adjuvant immunotherapy. Willingness-to-pay was lower for patients with incomes that were lower rather than higher: US$595 (95% CI US-$555 to 1,305) and US$1,638 (95% CI US$ -1,235 to 3,419) per year for adjuvant immunotherapy with an absolute reduction of 1% in the 3-year risk of recurrence. Conclusions: Almost three-quarters of patients preferred adjuvant immunotherapy over observation without adjuvant immunotherapy. Patients were more likely to select immunotherapy if the risk of melanoma recurrence and the chance of fatal AE were reduced. Understanding patient preferences and acceptable trade-offs for adjuvant immunotherapy may allow better-informed decisions for individuals and assist policymakers in decisions about access and subsidization of effective and expensive treatments.

A tale of two modes: Who will use single user and shared autonomous vehicles

The two most traditional and conventional transportation modes, private vehicles, and public transit, may be disrupted due to the advent of shared autonomous vehicles (SAVs), which can offer affordable on-demand mobility solutions leading to a transformed transportation system. However, little is known about the attributes affecting mode choice decisions and the impacts of the emergence of SAVs on travel behavior. A stated preference survey consisting of choice experiments, distributed online in October and November 2017 to residents of the Chicago-Naperville-Elgin, IL-IN-WI metropolitan statistical area, is used to determine the perceived impacts that SAVs may have on mode choice decisions and the corresponding value of travel time savings. Based on a representative sample (in terms of age and gender) of 400 responses, random parameter (mixed) logit models are developed to investigate the factors that affect mode choice decisions in short- and long-term scenarios. Value of travel time savings (VTTS) is calculated using the marginal rate of substitution derived from the mixed logit models. The results indicate that the option of sharing the AV ride is not as preferable as single occupant AVs across all market segments, which may challenge the benefits that this emerging technology can bring to shared transportation modes. Further, it was found that VTTS is lower for SAVs compared to single occupancy AVs regardless of the time horizon.

Influencing factors of trucking companies willingness to shift to alternative fuel vehicles

Freight transportation is a manifestation of a vibrant economy, but it is also associated with negative externalities such as greenhouse gas emissions. To mitigate these impacts, freight vehicles using alternative fuels have been developed, but they are not widely adopted. Moreover, there is not much information on the factors that could incentivize trucking companies to adopt such vehicles, especially in emerging economies where diesel engines dominate the market. Using Colombia as a case study, this paper aims to evaluate the factors that influence businesses to shift towards acquiring trucks powered by alternative fuels, applying an econometric approach based on discrete choice models. Results suggest that demand for alternative fuel vehicles (AFVs) is highly sensitive to purchase costs, operational range, and environmental awareness. Hybrid fuel alternatives seem to be preferred over electric and compressed natural gas vehicles. The analysis is supplemented with the estimation of marginal substitution rates, elasticities, and the simulation of scenarios considering subsidies and tax exemptions, from which we identify implications and draw policy recommendations to promote the use of AFVs.

Divine Proportion of The Invisible Hand: a New Look at Adam Smith’s Natural Theology

Recent research on labor-search-leisure model has described local multiple equilibria of Invisible hand under wage and price dispersion. This paper analyzes the general competitive equilibrium, where the Invisible hand creates harmonic proportions of mutually beneficial exchange. The analysis results in the rigorous mathematical proof that at the general competitive equilibrium both the marginal rate of substitution of leisure for consumption and marginal rate of transformation of production into services are equal to the golden ratio conjugate, whereas both the intensity of consumption and the sales-costs of production ratio are equal to the golden ratio itself, also called the divine proportion. On commodity market the golden ratio conjugate equalizes the gravitation or attractiveness of both seller and buyer. Local monopoly and monopsony disappear, and the competitive equilibrium really becomes perfect. In marriage markets the golden ratio conjugate equalizes the attractiveness of both man and woman and creates the ideal family. These results bring us back to the theological grounds of Adam Smith’s works; it gives a new view on his idea of natural rates of both wages and profit. It really can be argued that there was a good reason to apply the natural theology approach to the analysis of exchange at times of the ‘Wealth of Nations’.

How does biased technological progress affect haze pollution? Evidence from APEC economies

Biased technological progress is the act of energy conservation and emission reduction by changing the marginal rate of substitution. In this study, we introduced renewable energy into a production function, and proposed a method of identifying biased characteristics of technological progress, based on marginal productivity theory. A panel dataset for the Asia-Pacific Economic Cooperation (APEC) economies from 2000 to 2017 was analyzed to explore the effect of biased technological progress in reducing particulate matter (PM2.5). We found that input biased technological progress tended to use more non-renewable energy. Input biased technological progress aggravated haze pollution; however, this effect decreased as the PM2.5 concentration increased. Output biased technological progress significantly reduced haze pollution in high-income economies, but increased it in low-income economies. The effect of neutral technological progress on haze pollution was the opposite of the effect from output biased technological progress. We also found that increasing renewable energy consumption and reducing energy intensity were separate effective paths for input and output biased technological progress, respectively, to mitigate haze pollution. For neutral technological progress, improving total factor productivity was an important way to mitigate haze pollution. Finally, several policy recommendations are proposed to mitigate haze pollution in APEC economies.

Valuing quality in mental healthcare: A discrete choice experiment eliciting preferences from mental healthcare service users, mental healthcare professionals and the general population

High and sustained healthcare quality is important worldwide, though health policy may prioritise the achievement of certain aspects of quality over others. This study determines the relative importance of different aspects of mental healthcare quality to different stakeholders by eliciting preferences in a UK sample using a discrete choice experiment (DCE). DCE attributes were generated using triangulation between policy documents and mental healthcare service user and mental healthcare professional views, whilst ensuring attributes were measurable using available data. Ten attributes were selected: waiting times; ease of access; person-centred care; co-ordinated approach; continuity; communication, capacity and resources; treated with dignity and respect; recovery focus; inappropriate discharge; quality of life (QoL). The DCE was conducted online (December 2018 to February 2019) with mental healthcare service users (n = 331), mental healthcare professionals (n = 510), and members of the general population (n = 1018). Respondents’ choices were analysed using conditional logistic regression. Relative preferences for each attribute were generated using the marginal rate of substitution (MRS) with QoL as numeraire. Across all stakeholders, being treated with dignity and respect was of high importance. A coordinated approach was important across all stakeholders, whereas communication had higher relative importance for healthcare professionals and service users and ease of access had higher relative importance for the general population. This implies that policy could be affected by the choice of whose preferences (service users, healthcare professionals or general population) to use, since this impacts on the relative value and implied ranking of different aspects of mental healthcare quality.

Understanding what matters to metastatic castration-resistant prostate cancer (mCRPC) patients when considering treatment options: A US survey.

80 Background: Nine new treatments for mCRPC, each varying in efficacy and safety, have been approved over the last 10 years, changing the landscape of patient management. Understanding how patients perceive and value the efficacy, safety, and administration burden of these treatments can facilitate shared-decision making to determine optimal management. To our knowledge, this study is the first to elicit patient preferences for mCRPC treatments in the US. Methods: We conducted a cross-sectional survey using the discrete-choice experiment (DCE) method, in which participants were asked to state their choices over successive sets of treatment alternatives, defined by varying levels of treatment characteristics (i.e., attributes). Six treatment attributes in this DCE were examined: overall survival (OS), months until patients develop a fracture or bone metastasis, likelihood of requiring radiation to control bone pain, fatigue, nausea, and mode of administration. The levels taken by each of these attributes were selected to reflect clinical practice. Quota sampling was used in an online panel for recruitment to ensure that study sample is representative of the US prostate cancer population by age distribution. The choice responses were used to determine the value (i.e., preference weights) respondents placed on each attribute via the use of conditional and mixed logit models. The importance of attributes and marginal rates of substitutions were also calculated in order to understand how much patients were willing to trade off between different attributes. Results: The final dataset included 160 participants, with a mean age of 71.6 years old and a mean of 8.96 years since prostate cancer diagnosis. Participants noted their preferences for mCRPC treatments characteristics as follows (in decreasing order of importance over the attribute ranges included in the study): OS (relative attribute importance [RAI]: 31%), reduction in the need for bone pain control (23%), nausea (16%), months until patients develop a fracture or bone metastasis (15%), fatigue (11%), and mode of administration (3%). The marginal rates of substitution demonstrated that eliminating moderate nausea was perceived as equivalent to a 1.9-month reduction in OS, and a reduction of fatigue from severe to mild was perceived as equivalent to a reduction in OS of approximately 3.3 months. Conclusions: Improving OS remains the highest priority, but patients are willing to sacrifice some survival to avoid declines in quality of life, including avoiding bone pain/fracture, nausea, and fatigue, in the mCRPC disease state.

Incorporating quality in economic regulatory benchmarking

The Danish water regulator uses, amongst other things, Data Envelopment Analysis to create a pseudo-competitive environment for the water companies. The benchmarking results are used to set an individual revenue cap for each company. The benchmarking model is currently criticised for not including the companies’ supply quality and thereby having an omitted variable bias problem. One problem the regulator has encountered when trying to incorporate supply quality in the benchmarking model is that it tends to increase the revenue caps more than desired. The regulator does, however, not have any prior information about the marginal rates of substitution between the quality variables and costs, which makes it challenging to reduce the supply quality's impact on the revenue caps.In this paper, we analyse the facet structure when incorporating three quality variables into the existing benchmarking model. We argue that it is generally sensible to investigate the facet structure and ensure that it is trustworthy before calculating efficiency scores, to increase the credibility of the results.By using an outlier detection model on the estimated marginal rates of substitution, we use the insights into the facet structure to create weight restrictions between costs and quality. This can help the regulator incorporate quality in the model without allowing the efficiency scores to increase excessively due to the increase in dimensionality. In addition, our proposed method reduces the need to extract the companies’ private information about their marginal rates of substitution, which is costly to verify for both the companies and the regulator. Lastly, we propose to add weight restrictions based on the consumer's willingness to pay for quality to avoid the companies choosing a level of quality that is higher than what the consumers are willing to pay for.

Population preferences for non-pharmaceutical interventions to control the SARS-CoV-2 pandemic: trade-offs among public health, individual rights, and economics

ProblemPolicymakers must decide on interventions to control the pandemic. These decisions are driven by weighing the risks and benefits of various non-pharmaceutical intervention alternatives. Due to the nature of the pandemic, these decisions are not based on sufficient evidence regarding the effects, nor are decision-makers informed about the willingness of populations to accept the economic and health risks associated with different policy options. This empirical study seeks to reduce uncertainty by measuring population preferences for non-pharmaceutical interventions.MethodsAn online-based discrete choice experiment (DCE) was conducted to elicit population preferences. Respondents were asked to choose between three pandemic scenarios with different interventions and impacts of the Corona pandemic. In addition, Best–worst scaling (BWS) was used to analyze the impact of the duration of individual interventions on people’s acceptance. The marginal rate of substitution was applied to estimate willingness-to-accept (WTA) for each intervention and effect by risk of infection.ResultsData from 3006 respondents were included in the analysis. The DCE showed, economic effect of non-pharmaceutical measures had a large impact on choice decisions for or against specific lockdown scenarios. Individual income decreases had the most impact. Excess mortality and individual risk of infection were also important factors influencing choice decisions. Curfews, contact restrictions, facility closures, personal data transmissions, and mandatory masking in public had a lesser impact. However, significant standard deviations in the random parameter logit model (RPL) indicated heterogeneities in the study population. The BWS results showed that short-term restrictions were more likely to be accepted than long-term restrictions. According to WTA estimates, people would be willing to accept a greater risk of infection to avoid loss of income.DiscussionThe results can be used to determine which consequences of pandemic measures would be more severe for the population. For example, the results show that citizens want to limit the decline in individual income during pandemic measures. Participation in preference studies can also inform citizens about potential tradeoffs that decision-makers face in current and future decisions during a pandemic. Knowledge of the population’s preferences will help inform decisions that consider people’s perspectives and expectations for the future.Survey results can inform decision-makers about the extent to which the population is willing to accept certain lockdown measures, such as curfews, contact restrictions, lockdowns, or mandatory masks.

Analyzing pedestrian behavior when crossing urban roads by combining RP and SP data

Considering the high crash rates involving pedestrians on urban roads, it is highly relevant to understanding pedestrian crossing behavior. This paper is the first to combine stated preference (SP) and revealed preference (RP) data to evaluate the impact that individual attributes, trip characteristics, built environment, strategies to prevent unauthorized crossing, and traffic flows have on pedestrians crossing decisions in an urban context. SP and RP surveys were designed and collected in Barranquilla (Colombia) near pedestrian bridges or signalized intersections where direct crossings and a high concentration of pedestrian fatalities related to traffic accidents exist. A logit model was estimated using the data enrichment paradigm. Results show that pedestrians weigh risks and costs when choosing how to cross the road. The trajectories observed in the RP component suggest that people prefer direct crossings; nevertheless, pedestrian bridges and signalized intersections can be attractive alternatives if their location matches the origin or destination of the crossing, and no detour is needed to use them. Waiting time; safety; the fine imposed for jaywalking; personal security, and previous decisions are also variables that influence pedestrian behavior when crossing urban roads. These results can be helpful to urban planners and decision-makers interested in proposing appropriate pedestrian infrastructure. The data pooling technique and the inclusion of a cost-related variable (i.e., fine) allowed computing the willingness to pay and marginal substitution rates for attributes of the built environment and other characteristics associated with the crossing decision. Also, the inclusion of several crossing alternatives and situations allowed assessing pedestrian crossing preferences under different scenarios.

Harmonious interaction of a smart organization and a smart city to activate digital transformations

Based on the modified production function, economic and mathematical modeling of production factors was carried out in the conditions of the development of a smart transport organization (Municipal public enterprise «Tulgorelektrotrans») and a smart city. The trends and methods of interaction between a smart organization and a smart city are proposed for the transformation of the digital economy of the city and the implementation of the goals of harmonious development. The existing scientific and methodological approaches to simulating the digital development of economic systems are systematized. On the basis of the modified production function, the substantiation of qualitative and quantitative changes in production factors for the smart city of Tula and smart organizations, taking into account the "digital" factor, is carried out. Formal dependencies made it possible to conduct a numerical assessment of the "smart" factor in the production of its own volume of shipped goods, completed works and services (for the city of Tula as a whole and for certain types of economic activity). The marginal rate of substitution by the smart labor factor was 2.28, and capital – 0.66.

Application of the Techniques of Determinants to Utility Maximization for a 4-Period Age-Specific Inter-Temporal Budget Constraints

The Lagrange multiplier (LM) method was used to derive a mathematical formulation to work out an optimal solution for a 4-period overlapping generation model with autonomous consumption to maximize a lifetime utility for households subject to age-specific inter-temporal budget constraints. In this paper, the use of Cramer’s rule is exhibited in finding the critical point where utility is maximized and to further test for sufficient conditions using the Hessian determinants to check if there is a local maximum in the critical point C utility is maximized. The use of the inter-temporal marginal rate of substitution was implored to show the future growth path of utility maximization an analytical argument was used to support such finding.

Refined choice set generation and the investigation of multi-criteria transit route choice behavior

To best make informed public transportation decisions, agencies must be aware of how individuals interact with the transit system. The key question to consider is how do passengers get from Point A to Point B and which attributes of the transit trip have the largest influence on that choice? To more accurately understand passengers’ interaction with transit systems, a new method for transit route choice estimation is proposed. This method modifies and builds upon a schedule-based forward label setting multi-criteria shortest path algorithm by introducing an iterative trip elimination methodology. This new methodology yields high quality transit path choice sets with exact regeneration of 70.5% of the observed paths. Moreover, detailed temporal information on all types of network links (in-vehicle, walking, and waiting) are produced with reasonable computational time of 0.5 s per path calculation and 6.9 s per individual’s choice set generation. This increased specificity, in turn, heightens the validity and accuracy of the route choice model. Passenger information is sampled from a transit on-board survey containing origin–destination locations, demographic details, and trip-specific attributes. A multinomial logit model with stop-level path size correction term is estimated. This estimation yields a 67% recovery rate between the path with the highest estimated likelihood and the surveyed (taken) transit path. Furthermore, a transfer penalty of 28.8 min was estimated while the marginal rates of substitution for the waiting and walking time coefficients are in close alignment with similar values in the literature. Express bus routes were found to have a statistically significant negative impact on path utility for the lowest income thresholds while transitways (light rail, bus rapid transit, or commuter rail) had a positive associated perception for the highest household income class. Thus, support is found for the claim that transitways can potentially attract higher-income “choice” riders to the transit network. The results of this research can be used to improve ridership projections and highlight areas for policy improvements that could have the largest impact on retaining and attracting new passengers to the transit system.

Patient and retina specialists' preferences in neovascular age-related macular degeneration treatment. A discrete choice experiment.

Neovascular age-related macular degeneration (nAMD) leads to severe and permanent visual impairment, significantly impacting patients' quality of life and functional independence. Although treatment with anti- vascular endothelial growth factor (VEGF) prevents and, in some cases, reverses visual damage, the need for frequent monitoring visits and intravitreal injections represents a significant burden on patients, caregivers and retina specialists. To elicit preferences for nAMD treatment characteristics from the perspectives of patients and retina specialists. A discrete choice experiment was conducted. Participants (patients > 50 years with nAMD receiving anti-VEGF drugs for at least 2 years and without previous experience with anti-VEGF and retina specialists working in the Spanish National Healthcare System) were asked to select one of two hypothetical treatments resulting from the combination of five attributes (effects on visual function, effects on retinal fluid, treatment regimen, monitoring frequency, and cost); their levels were identified by reviewing the literature and two focus groups. The relative importance (RI) given to each attribute was estimated using a mixed logit model. The marginal rates of substitution (MRS) were calculated taking cost as the risk attribute. A total of 110 patients (P) [aged 79.0 (SD:7.4) years; 57.3% women; 2.3 (SD:0.7) years with nAMD; 2.1 years (SD:0.1) in treatment] and 66 retina specialists (RS) participated in the study. Participants gave greater RI to improvements in their visual function [60.0% (P); 52.7% (RS)], lower monitoring frequency [20.2% (P); 27.1% (RS)] and reduction in retinal fluid [9.8% (P); 13.0%(RS)]. Patients and retina specialists would agree to an increase in cost by 65.0% and 56.5%, respectively, in exchange for improvements of visual function; and 25.5% and 43.3% on delaying monitoring frequency by one month. Efficacy of treatment, in terms of visual function improvements, is the main driver for treatment election for both patients and retina specialists. Treatment monitoring requirements are also considered, mainly from the retina specialist's perspective. These results suggest that the use of more efficacious anti-VEGF agents with a longer duration of action may contribute to aligning treatment characteristics with patients/specialists' preferences. A better alignment would facilitate better disease management, fulfilling the unmet needs of patients and retina specialists.

The efficacy of the dependent care deduction at maintaining diet quality

One feature of the SNAP benefits calculation, the Dependent Care Deduction, increases SNAP benefits if a household pays for formal care, allowing for an indirect substitution between household time spent in dependent care and SNAP benefits. Approximately only 3 percent of eligible households utilize the Dependent Care Deduction, despite many eligible households facing significant time constraints. Therefore, I investigate the reduction in childcare time needed for a household to maintain their level of diet quality if they were to select into paid childcare. Using the American Time Use Survey I predict time spent in numerous activities for households in the National Household Food Acquisition and Purchase Survey. In particular, I focus on secondary childcare time, time where the caregiver is completing a separate task while responsible for the well-being of a child because it is the dependent care activity reduced most by formal childcare. Estimating a conditional hybrid diet quality production function, I find that the marginal rate of substitution between household income and secondary childcare is higher for lower income levels and more time-constrained households. In addition, I find the necessary reduction in secondary childcare time to hold diet quality constant is approximately 5.3 h per day for all households and 3 h per day for SNAP households, assuming the average cost of one four-year old child in formal care.

A Praxeological Theory of Interest Rates

This paper starts with the observation that the pure time preference theory leads to conflicting views concerning the effect of changes in productivity on the rate of interest. Subsequently, it reviews parts of the interest literature and concludes that the pure time preference theory does not qualify as a praxeological theory. Then, the paper combines Hülsmann’s theory of interest with the subjectivist capital theory of Lachmann and Kirzner and provides a praxeological theory that explains the rate of interest. The key to that theory is that cost reduction through the use of fixed capital must always be understood as relative to the costs of labor which the capital replaces. Since labor is non-specific and the price of labor therefore also constitutes the production costs of fixed-capital goods to a certain extent, the use of fixed capital necessarily entails a business surplus somewhere in the economic system. Since this surplus cannot dis-appear it qualifies as interest income. The size of this income is such that the interest rate corresponds to the marginal rate of substitution between labor and fixed capital as embodied in entrepreneurial actions.

EXTENSIVE AND INTENSIVE REPRODUCTION: THE RATIO OF ECONOMIC GROWTH FACTORS

The article is devoted to the development of method for estimating the ratio of extensive and intensive factors of economic growth and its use to assess the situation in the Ukrainian economy. Extensive development, which is based on the quantitative growth of the factors of production used at certain stages, can provide the desired increase in GDP. However, from a historical perspective, their potential is limited. Therefore, the global trend is the strengthening of intensive factors, which are based on the growth of the impact of production factors, their constant improvement on the basis of modern innovation processes. The author conducted a critical analysis of the existing options for calculating the ratio of extensive and intensive factors of economic growth and proposed his own method, which involves the use of the marginal rate of substitution of production factors to calculate their total volume. Its viability was tested in the analysis of economies of developed countries. However, it was impossible to use this approach to assess the Ukrainian economy due to considerable subjectivity in the formation of statistical information, primarily on the value of fixed assets. Correlation analysis did not show a close relationship between labor productivity and its capital adequacy. At the same time, the use of methods of indirect assessment of the resources involved in production and comparing their dynamics with the dynamics of GDP allowed us to say that in those periods when the economy showed overall growth (2001–2005 and 2016–2019), its main source was extensive factors, which grew significantly ahead of production volumes. As a result, indicators of resource efficiency have deteriorated. On the contrary, during the crisis situations (2006–2010 and 2011–2015) the volumes of production factors used either did not increase, or even decreased altogether. This is especially true of gross savings. The reduction in production to a lesser extent than the reduction in the amount of used resources was achieved precisely by increasing their return. The amount of used resources is more sensitive to crises than the efficiency of their use. This is evidenced by the analysis of data for 2009 and 2014–2015, when Ukraine’s real GDP declined. In general, GDP growth in our country is achieved solely due to extensive factors, while their impact remains extremely low. Therefore, without an innovative breakthrough, Ukraine has very little chance to reduce its lag behind the world.

Analysis of Marginal Rates of Substitution in the Presence of Undesirable Factors Using Data Envelopment Analysis

Analysis of Marginal Rates of Substitution in the Presence of Undesirable Factors Using Data Envelopment Analysis

Carbon emissions, consumption structure upgrading, and high-quality economic development: empirical evidence from China

Environmental influence on the economy can be enhanced by consumption upgrading, transforming the key driver of economic development from supply to demand. This study constructs a model for consumption upgrading and applies threshold regression based on the susceptible–infectious–recovered (SIR) model, to explore the role of carbon emissions on high-quality economic development. The results reveal that the environmental input characterized by carbon emissions has an inverted U-shaped effect on high-quality economic development. A diminishing marginal rate of substitution of economic output demand to environment demand is observed during consumption upgrading. This study proves that environmental resources can assume both supply and demand roles for economic output and customers, which gradually emerge during consumption upgrading.

Preferences regarding emerging HIV prevention technologies among Toronto men who have sex with men: a discrete choice experiment

New forms of HIV pre-exposure prophylaxis (PrEP) include long-acting injectables and topical microbicides, each with unique attributes that may appeal to distinct users. We used a discrete choice experiment to characterize preferences for new PrEP formulations among Toronto men who have sex with men. MSM undergoing anonymous HIV testing completed a discrete choice experiment with 12 choice sets by selecting their preferred option within each set. Each set included “usual methods to prevent HIV” (excluding PrEP) as one alternative and two hypothetical PrEP alternatives, which differed according formulation/dosing, side effects (none/mild), risk of drug resistance (none/low/moderate), and HIV prevention efficacy (50%, 65%, 80% or 99% risk reduction). We used mixed logistic regression to infer preferences for PrEP attributes and calculate the marginal rate of substitution between efficacy and other PrEP attributes. 306 men with median (interquartile range) age = 29 (25, 36) years participated, and reported 6 (3, 10) partners and 0 (0, 2) condomless receptive anal sex acts in the preceding six months. An on-demand pill was the most preferred formulation, followed by a monthly injection, daily pill, and on-demand rectal gel. Drug resistance was an important determinant of preferences if the risk was moderate, but not if it was low. The minimum efficacy required for an on-demand pill to be preferred over no PrEP was 32.6% (95%CI = 21.2–43.9%); for a daily pill, injections, and rectal gel, minimum efficacy was 57.9% (95%CI = 44.1–71.7%), 40.1% (27.0–53.2%), and 71.3% (60.5–82.1%), respectively. Attitudes towards PrEP formulations vary among men who have sex with men, with on-demand pills and monthly injections having the highest average preference scores. Understanding these preferences may help to predict uptake.