Efficiency Gap Research Articles

Enhancing online-to-offline delivery efficiency facilitated by Industry 4.0: a personnel configuration perspective

PurposeThe overuse and scarcity of resources emphasize the importance of the circular economy. The technology facilitated by Industry 4.0 stimulates the implementation of the circular economy that aims to reduce resource use and enhance operational efficiency. This study focuses on enhancing delivery efficiency in an online-to-offline (O2O) context from an Industry 4.0 technology-facilitated personal configuration perspective, that is, comparing in-house and crowdsourced delivery efficiency in China's O2O on-demand food delivery context.Design/methodology/approachThe authors collect 128,152 orders from 38 restaurants of an online restaurant chain in China. The authors adopt multiple regression analysis to examine the delivery efficiency gap between in-house and crowdsourced deliverymen and the determinants of this efficiency gap.FindingsThe findings of this study reveal that crowdsourced deliverymen exhibit higher delivery efficiency, in terms of a shorter delivery time, than in-house deliverymen. In addition, the authors find that platforms providing monetary incentives or implementing late delivery penalties enlarge this efficiency gap. Furthermore, the authors show that external factors, such as working on weekends and bad weather conditions, contribute to the narrowing of this performance efficiency.Practical implicationsThe study's findings suggest that platforms should use advanced technologies facilitated by Industry 4.0 to optimize their personnel configuration to enhance their delivery efficiency and reduce carbon emissions. The effective approaches include using financial incentives and improving working schedules.Originality/valueThe authors' findings contribute to the online fulfillment literature by focusing on delivery efficiency in the O2O context from the Industry 4.0 technology-facilitated personnel configuration perspective. The authors examine how internal and external factors moderate the performance efficiency between these two types of deliverymen.

Experimental study of a full-scale hexagonal wet electrostatic precipitator for collection of black carbon and particulate matter generated by a marine diesel engine

ABSTRACT Wet electrostatic precipitators have demonstrated a robust capability for removal of particulate matter by minimizing back corona and particle re-entrainment of fine particles. The absence of studies investigating the removal of black carbon particles using a wet electrostatic precipitator requires additional development/investigations. Among the operational parameters of wet electrostatic precipitators, particle residence times (<1 s) and the amount of electrostatic energy transferred to the exhaust gas are important to determine the removal efficiencies of wet electrostatic precipitators. This article reports the removal efficiency of black carbon, total particulate matter, and various particle sizes using different operating conditions in a full-scale hexagonal wet electrostatic precipitator column with sequential cleaning. The exhaust gas cleaned during the experiments was produced by a 2 MW marine engine operated on heavy fuel oil. Three key parameters, voltage-current characteristics, transferred electrostatic energy to the exhaust gas, and particle residence times were varied to evaluate their effects on removal efficiencies. The wet electrostatic precipitator was able to remove from 42.7% to 97.2% of the particulate matter and 44.8% to 95.9% of black carbon particles by varying the electrical energy input to the gas stream (5–262 J/m3) and the particle residence time (0.3–1.8 s). A change in particle residence time (0.3 to 0.95 s) showed an overall removal increase of 31.7% and revealed removal efficiency gaps of up to 24.1% between particle sizes. By investigating the removal efficiencies of different particle sizes and black carbon content, it was found that the best fit was achieved for sizes between 0.02 and 0.77 μm, indicating a black carbon size range in this order. The study indicates that a similar removal efficiency between black carbon and particulate matter could be achieved and that the main focus for improvement of black carbon removal should be found in the particle range between 0.02 and 0.77 μm. Implications: The manuscript describes a small efficient system for the removal of particle matter and black carbon particles from the exhaust gas generated by a ship engine. This manuscript is especially interesting for the International Maritime Organization (IMO) and its sub-committee on Pollution Prevention and Response (PPR). The IMO is the law-maker/the United Nations specialized agency with responsibility for atmospheric pollution by ships in international waters. The IMO agreed in 2011 on an investigation plan to gather information and to find possible black carbon control measures for future regulations, which to some extent can be delivered through this article.

Performance Evaluation of Water Services in Italy: A Meta-Frontier Approach Accounting for Regional Heterogeneities

Data relative to the water services industry in Italy indicate that there is a serious infrastructure gap between the southern regions and isles and the rest of the country. In these geographical areas, water utilities are provided with substantial public grants from the central and local governments to support investments necessary to mitigate the infrastructure divide by increasing capacity and improve service quality. This paper implements a meta-frontier non-parametric approach based on a data envelopment analysis (DEA) to evaluate the efficiencies of 71 Italian water utilities, accounting for the differentiated contexts in which they operate. A short-term perspective was assumed to estimate efficiency, considering the production factors associated with the infrastructure assets as non-discretionary inputs in the specification of the meta-frontier model. The results showed that water utilities operating in the southern regions and isles suffer from an efficiency gap in comparison to those in the northern and central regions. The average efficiency gap was 9.7%, achieving 24.9% in the worst case. Moreover, a more in-depth analysis focusing on the water utilities in the southern regions and isles indicated that scale inefficiencies might be an important determinant of such an efficiency gap. Indeed, slightly more than 69% of the water utilities operated at increasing returns to scale. Evidence from this study raises concern about the appropriate structure of the Italian water service industry and, particularly, the optimal size of the utilities and the financial sustainability of water services in the southern regions and isles.

Optimal nationalization policy in a heterogeneous mixed oligopoly

AbstractThis study constructs a mixed oligopoly model considering product differentiation, the proportion of state‐owned shares, the efficiency gap, and the reform cost, investigates market equilibrium under different competition modes, and discusses the optimal proportion of state‐owned shares. Product differentiation, the proportion of state‐owned shares, and reform costs have complex impacts on the equilibrium results. Complete, partial, and no nationalization may be optimal under certain conditions. The competition mode affects welfare distribution among stakeholders. The government should decide on an optimal nationalization policy according to specific conditions and the market environment.

Estimating the efficiency gap of maize yield across different irrigation methods in Pakistan

AbstractThis study was carried out to identify and compare the efficiency levels of maize growers using surface water irrigation (SWI) and groundwater irrigation (GWI) in Khyber Pakhtunkhwa, Pakistan. The variance inflation factor and Koenker Bassett test were used to check multicollinearity and heteroscedasticity that mostly occur in the primary data. The empirical findings obtained from the stochastic frontier analysis show that irrigation plays a significant role in the maize yield in both the SWI and GWI groups. The results revealed that irrigation was the most effective input used by the growers and could significantly increase the production of maize for SWI and GWI by 26 and 11%, respectively. The projected mean efficiency of the study implies that the SWI and GWI groups can still increase their efficiency by 11.1 and 19.3% with a given amount of inputs. The various inefficiency factors used in the study significantly contribute to the efficiency level of maize growers. It is also observed that farmers with large landholdings are more willing to pay for surface water irrigation, followed by farmers who are in touch with extension agents. Based on these findings, the study also recommends some policies for increasing maize production.

Can rivalry in R&D be harmful under supply function competition?

We consider a duopoly with cost asymmetry and demand uncertainty and show that rivalry in (process) R&D can be extremely harmful to both firms even in the presence of spillovers if the firms produce under supply function competition. However, if they produce under Cournot competition, firms can earn higher profits in the presence of R&D rivalry than what they could earn when they (mutually) invested in no R&D. We also show that R&D rivalry always works to widen the efficiency gap between the firms under Cournot competition, and also under supply function competition if R&D spillovers are present. On the other hand, consumers’ welfare is affected by R&D rivalry only under supply function competition. Under this competition, consumers always prefer the presence of R&D rivalry with or without spillovers to the absence of R&D rivalry; however, they obtain their highest surplus under R&D rivalry when there are no R&D spillovers.

Facile surface homojunction reconstruction in halide perovskite solar cells

Perovskite solar cells (PSCs) have attracted great attentions due to their excellent photovoltaic performance. Further improvement of device efficiency is limited by the recombination of the charge carriers even a heterojunction-based architecture is employed. Herein, we discovered that a simple surface modification of the perovskite film by incorporating isopropyl alcohol (IPA) post-treatment could convert the top surface to be more n-type, which spontaneously formed an n/n + homojunction between the bulk (weak n type (n)) and the surface (more n-type (n + )) in a single perovskite film. A reconstruction toward a PbI 2 -rich top surface was induced by the remove of excess formamidinium iodide dissolved in a polar solvent IPA. This reconstructed n/n + homojunction lead to the enlarged built-in electric field for efficient charge separation and transport of the photogenerated carriers. The inverted PSCs with the reconstructed n/n + homojunction contribute to improve efficiency and narrow their efficiency gap with conventional n-i-p type devices. Our result suggests that the homojunction structure is an effective approach to reduce carrier recombination loss and achieve highly efficient PSCs. • A facile surface homojunction reconstruction is achieved by solvent treatment. • A PbI 2 -rich perovskite surface is induced by the remove of excess FAI. • The reconstructed n/n + homojunction brings about the enlarged built-in electric field. • The reconstructed n/n + homojunction contributes to improved photovoltaic efficiency.

The roadmap towards the efficiency limit for supercritical carbon dioxide coal fired power plant

The Chinese Government has issued a series of documents to explain China’s control over the carbon dioxide (CO2) emission. One of the major tasks is to develop higher efficiency coal fired power plant, compared with current running power plant. In this paper, we aim to explore the roadmap to reach the efficiency limit for coal fired power plant using supercritical carbon dioxide cycle (sCO2 cycle). Referenced to Carnot cycle, the proposed roadmap is to increase the cycle efficiency by elevating average heat absorption temperature (Tave,h) and lowering average heat release temperature (Tave,l). In contrast to recompression cycle (RC), tri-compression cycle (TC) is introduced. Due to the increased Tave,h, TC achieves the second largest contribution for efficiency increment, followed by the reheating technique. Then, TC, double reheating (DRH) and intercooling (IC) are integrated as TC + DRH + IC in the power plant. To completely absorb flue gas energy over entire temperature range of (1500 ∼ 120) °C. A top cycle and a bottom cycle are connected for cascade utilization of flue gas energy. Overlap energy utilization is further utilized to fill the efficiency gap between top and bottom cycles. The proposed cycle also integrates the module boiler design to suppress the pressure drop penalty, and the flue gas recirculation to keep the heater surface temperature in an accepted level. A numerical model is developed for the comprehensive sCO2 cycle. At the main vapor parameters of 35 MPa/630 °C, the sCO2 coal fired power plant reaches the net power generation efficiency of 51.03%, which is higher than 48.12% for a supercritical water-steam power plant at the same capacity. Such efficiency improvement saves 175.2 kilotons of coal and reduces 396.4 kilotons of CO2 emission for 1000 MW capacity in a fascial year. Our work provides the guideline for the design and operation of large scale sCO2 coal fired power plant.

Cu2ZnSnS4 QDs anchored 2-D few-layer graphene bridge enhanced photo induced charge carrier transport behavior for high efficient kesterite photovoltaic cell

Quaternary chalcogenide Cu2ZnSnS4 (CZTS) is a promising absorber for photovoltaic cell application due to its excellent properties like natural abundancy, non-toxic material incorporation, high absorption coefficient ∼104 cm−1 and tuneable band gap energy of 1.4–1.6 eV. However, still there is a huge gap of efficiency between the market oriented Si based photovoltaic device and kesterite device as it is hindered by poor charge carrier mobility. To improve the carrier mobility of semiconducting CZTS material, incorporation of highly conducting material like graphene would be helpful. The incorporation of graphene into CZTS enhances the separation and transfer of charge carriers in an efficient way inhibiting recombination. In this present work, the photovoltaic performance of solution processed single phase kesterite CZTS QDs anchored on electro-chemically prepared few-layer graphene sheet (FLGS) as active layer has been reported. The QD decoration has been carried out by a simple, scalable, environment friendly solution based approach without surface modifications and post-sulphurization treatment. The prepared hybrid structure demonstrates significant increase in photocurrent and optical absorbance indicates the fast charge carrier transport behaviour. The power conversion efficiency (PCE) of fabricated hybrid CZTS QDs-FLGS photovoltaic cell with device configuration of Mo/CZTS QDs-FLGS/CdS/ZnO/Al approached ∼7.64% (for 2.5 wt% FLGS loading) with short circuit current density (Jsc) of 19.07 mAcm−2, superior to individual CZTS QDs (∼6.11% PCE and 15.6% Jsc).

Multiobjective Optimization for Politically Fair Districting: A Scalable Multilevel Approach

Gerrymandering has been a fundamental issue in American democracy for more than two centuries, with significant implications for electoral representation. Traditional optimization models for political districting primarily model nonpolitical fairness metrics such as the compactness of districts. In “Multiobjective Optimization for Politically Fair Districting: A Scalable Multilevel Approach,” Swamy, King, and Jacobson propose optimization models that explicitly incorporate political fairness objectives using political data from past elections. These objectives model fundamental fairness principles such as vote-seat proportionality (efficiency gap), partisan (a)symmetry, and competitiveness. They propose a solution strategy, called the multilevel algorithm, that solves large instances of the problem using a series of matching-based graph contractions. A case study on congressional districting in Wisconsin demonstrates that district plans balance the interests of the voters and the political parties.

Efficient Privacy-Preserving K-Means Clustering from Secret-Sharing-Based Secure Three-Party Computation.

Privacy-preserving machine learning has become an important study at present due to privacy policies. However, the efficiency gap between the plain-text algorithm and its privacy-preserving version still exists. In this paper, we focus on designing a novel secret-sharing-based K-means clustering algorithm. Particularly, we present an efficient privacy-preserving K-means clustering algorithm based on replicated secret sharing with honest-majority in the semi-honest model. More concretely, the clustering task is outsourced to three semi-honest computing servers. Theoretically, the proposed privacy-preserving scheme can be proven with full data privacy. Furthermore, the experimental results demonstrate that our proposed privacy version reaches the same accuracy as the plain-text one. Compared to the existing privacy-preserving scheme, our proposed protocol can achieve about 16.5×–25.2× faster computation and 63.8×–68.0× lower communication. Consequently, the proposed privacy-preserving scheme is suitable for secret-sharing-based secure outsourced computation.

Barriers to the efficiency of internal evaluation in Polish secondary schools

PurposeThe purpose of this study is to investigate the system of factors influencing the efficiency of internal evaluation in Polish secondary schools.Design/methodology/approachData collected in interviews with evaluation experts and teachers on the barriers to the efficiency of internal evaluation and their causes were subjected to a qualitative cause-and-effect analysis.FindingsFive barriers to the evaluation efficiency (6B model) and five actions of the school head stopping their impact (6A model) were identified. The latter include selecting the key evaluation function (3KEF model) and ensuring the conditions for efficiency in the improvement loop.Research limitations/implicationsAlthough the research was carried out in Polish schools, the conclusions indicate regularities affecting organizations throughout the world.Practical implicationsStudents’ educational needs may exceed the schools’ ability to meet them at class time mostly due to resource constraints. The implementation of the principle of equal opportunities in education requires continuous improvement of the efficiency of schools’ processes. Evaluation can help qualify tasks for improvement.Social implicationsThe level of engagement (reactive/active) of the school principal and teachers in evaluation and improvement is a crucial factor in overcoming the barriers to the efficiency of the school processes.Originality/valueThe ability to respond to the efficiency gaps of the school processes depends on the choice and efficiency of the KEF. The rationale for selecting the function and the schemes for its implementation have paradigmatic grounds.

Evolution trend and promotion potential of environmental efficiency of dairy farming in china from the perspective of “club convergence”

There are differences in resource endowments, environmental regulations, and production functional areas among different regions in China, which makes dairy farming have certain heterogeneity and imbalance in pollution control, which is mainly reflected in the differences in the environmental efficiency of dairy farming among regions. By analyzing the convergence trend of the dairy farming environment in different regions and scales, it is helpful to predict the potential of improving environmental efficiency, and promote the high-quality development of dairy farming. Based on the dairy farming data of 27 provinces (cities and districts) in China from 2004 to 2019, the SBM model of unexpected output was used to measure the environmental efficiency of dairy farming on different scales. It was found that there were certain differences in the environmental efficiency of dairy farming in China. The overall environmental efficiency of dairy farming showed a “U" evolution trend, including small-scale, medium-scale, and large-scale. The average values of their environmental efficiency were 0.6859, 0.6930, and 0.6855 respectively, and the environmental efficiency of medium-scale dairy farming was the best. The convergence analysis of environmental efficiency showed that there was a conflict between the traditional σ convergence and β convergence results. However, the club convergence showed that the environmental efficiency of small-scale dairy farming converged in general, which could be further divided into two club convergence. The environmental efficiency of medium-scale and large-scale dairy farming did not converge in general but did converge in four different clubs, respectively. Taking the highest environmental efficiency value in the “club” as the reference, the potential to improve the environmental efficiency of dairy farming in different sizes was calculated. The prediction results showed that the gap between the actual value and the potential value was narrowing. It is expected that the potential to improve the environmental efficiency of dairy farming in China will remain above 10% in the next 10–20 years. Based on the above studies, this paper put forward some policy suggestions, such as changing the development direction of dairy farming, changing scale expansion to structural upgrading, implementing differentiated environmental efficiency improvement strategies, narrowing the efficiency gap between regions, paying attention to the input-output structure of factors, and improving the efficiency of breeding environment from the perspective of “eating” and " emission ".

Toward High‐Efficiency Ultrahigh Numerical Aperture Freeform Metalens: From Vector Diffraction Theory to Topology Optimization

AbstractOptical metasurface is a 2D array of subwavelength meta‐atoms that arbitrarily manipulates amplitude, polarization, and wavefront of incident light, offering great advantages in miniaturization and integration. However, the presuppositions hidden in conventional unit‐cell‐based design approach, including discrete phase sampling, local periodicity approximation, and normal response, imply that the responses and interactions of meta‐atoms are almost impossible to be accurately modeled, thus impeding the effective design of high‐efficiency ultrahigh numerical aperture (NA) metalens. Here, based on vector diffraction theory and plane wave expansion method, theoretical limitation of metalens efficiency is comprehensively investigated. It is identified that for high‐NA metalens, theoretical focusing efficiency is limited by diffraction capability of vector field, while evanescent wave attenuation dominates theoretical efficiency decline for ultrahigh‐NA metalens. It is also shown that the efficiency of conventional metalens has a huge gap from theoretical limitation, owing to imperfect diffractive focusing and impedance mismatch reflections. To fill such efficiency gap, the high‐efficiency high‐NA freeform metalens based on topology optimization is further demonstrated. Particularly, topology geometric constraints are utilized to reduce minimum feature size while keeping high efficiency. The results could shed new light on the understanding and design of ultrahigh‐NA metalens and find promising applications in optical imaging, microscopy, and lithography.

Measuring Pollution Control and Environmental Sustainable Development in China Based on Parallel DEA Method

The purpose of this study is to explore the impact of pollution control on industrial production efficiency in 31 provinces and cities in the Yellow River and Non-Yellow River basins in China from 2013 to 2017, using the methods of the directional distance function (hereinafter referred to as DDF) and the technology gap ratio (hereinafter referred to as TGR) in parallel, while taking the industrial production sector (labor force, total capital formation, energy consumption and industrial water consumption) and the pollution control sector (wastewater treatment funds and waste gas treatment funds) as input variables. Undesirable outputs (total wastewater discharge, lead, SO2 and smoke and dust in wastewater) and an ideal output variable (industrial output value) are taken as output variables. It is found that the total efficiency of DDF in the Non-Yellow River Basin is 0.9793, which is slightly better than 0.9688 in the Yellow River Basin. Among the 17 provinces and cities with a total efficiency of 1, only Shandong and Sichuan are located in the Yellow River Basin. The TGR values of 31 provinces, cities and administrative regions are less than 1, and the average TGR value of the Yellow River Basin is 0.3825, which is lower than the average TGR value of the Non-Yellow River Basin of 0.5234. We can start by improving the allocation of manpower and capital, implementing the use of pollution prevention and control funds, improving the technical level of industrial production, improving pollutant emission, and increasing output value to improve overall efficiency performance. This study uses the parallel method, taking the industrial production department and the pollution control department as inputs, to objectively evaluate the changes in industrial production efficiency and technology gap in the Yellow River and Non-Yellow River basins, which is conducive to mastering the situation of pollution control and industrial production efficiency, and provides the reference for SDG-6- and SDG-9-related policy making.

Spatial-temporal investigation of green building promotion efficiency: The case of China

Green building, a significant sustainable practice to enhance the relationship between buildings and the environment, has received much attention worldwide. Although green buildings spread fast around the world, the efficiency of resources for green building construction has great potential to improve. Meanwhile, the spatial correlations of green building construction need to strengthen to benefit from the spillover effects . However, only few previous studies focused on efficiency problems in the green building promotion process and their spatial correlations. This study aims to propose a framework to examine green building promotion efficiency and investigate its spatial relationships between regions in different time slices. As a case study, data from 28 regions in China were collected. Data envelopment analysis and social network analysis were used to analyze the data. Results show that the overall green building promotion efficiency in China increased gradually, but significant efficiency gaps existed among regions. Regional collaborations made great contributions to efficiency enhancement, especially in the Beijing-Tianjin-Hebei, Yangtze River Delta and Pearl River Delta areas. Furthermore, only a small proportion of regions performed well in the efficiency and spatial correlations, mainly in southeast China. Most regions had low efficiency and weak correlations with the developed regions. This study contributes to the knowledge body of green buildings by presenting the first investigation into the green building promotion efficiency and the spatial correlations in green building development. The findings would enable researchers, policymakers and practitioners to develop efficient policies and strategies to promote the widespread implementation of green buildings.

Is there an energy efficiency gap in China? Evidence from an information experiment

We use an incentivized field experiment to test whether Chinese consumers underinvest in energy efficiency. We document that providing information to Chinese consumers on the energy costs of lightbulbs significantly increases their willingness to pay for energy-efficient bulbs, even among those who previously overestimated the savings from energy efficiency. Our results indicate that Chinese consumers are imperfectly informed, but that neither biased beliefs nor salience can explain their underinvestment in energy efficiency. Rather, we contend that consumers underinvest in energy efficiency because they are uncertain about the savings from energy efficient products.

Recent Criterion on Stability Enhancement of Perovskite Solar Cells

Perovskite solar cells (PSCs) have captured the attention of the global energy research community in recent years by showing an exponential augmentation in their performance and stability. The supremacy of the light-harvesting efficiency and wider band gap of perovskite sensitizers have led to these devices being compared with the most outstanding rival silicon-based solar cells. Nevertheless, there are some issues such as their poor lifetime stability, considerable J–V hysteresis, and the toxicity of the conventional constituent materials which restrict their prevalence in the marketplace. The poor stability of PSCs with regard to humidity, UV radiation, oxygen and heat especially limits their industrial application. This review focuses on the in-depth studies of different direct and indirect parameters of PSC device instability. The mechanism for device degradation for several parameters and the complementary materials showing promising results are systematically analyzed. The main objective of this work is to review the effectual strategies of enhancing the stability of PSCs. Several important factors such as material engineering, novel device structure design, hole-transporting materials (HTMs), electron-transporting materials (ETMs), electrode materials preparation, and encapsulation methods that need to be taken care of in order to improve the stability of PSCs are discussed extensively. Conclusively, this review discusses some opportunities for the commercialization of PSCs with high efficiency and stability.

Yield and Resource Utilization Efficiency Gap in Early Maturing Japonica Rice Cultivars under Different Management Strategies—A Different Location Investigation

High input costs and poor management options have resulted in a large rice yield gap. Thus, there is a need to reduce production costs and improve resource-use efficiency by using new cultivation techniques at different locations. The objective of this study was to determine yield and utilization efficiency gaps in early maturing japonica rice under four treatments; no nitrogen application (N0), local farmer practice (FP), high-yield, high-efficiency practice (HYP), and super-high-yield practice (SHY). The average yields under N0, FP, HYP, and SHY were 5012, 7356, 8448, and 9629 kg ha−1, respectively. Differences among treatments were as: N0 to FP (gap 1); FP to HYP (gap 2); and HYP to SHY (gap 3). Yield gaps 1, 2, and 3 were 2337, 1092, and 1181 kg ha−1, respectively. Yield gap was positively associated with panicles per square meter. Yield under HYP and SHY was 14.8% and 30.9% higher than that under FP, respectively. This increase in yield was mainly associated with a higher number of panicles. For resources, gaps 1, 2, and 3 were as follows: water-use efficiency, 0.1706, 0.1513, and 0.1089 kg m−3; radiation-use efficiency, 0.3285%, 0.1780%, and 0.0941%; and heat-use efficiency, 1.8685, 1.0339, and 0.8798 kg °C−1 d−1 ha−1, respectively. The yield was positively correlated with water, radiation, and heat-use efficiencies. The differences in yield and resource-use efficiency were significant between sites. A reduction in yield and efficiency gaps can ensure sufficient panicle per square meter, stabilize grain number per panicle, and increase harvest index and biomass. Overall, HYP is a promising option to increase the yield of early maturing japonica rice yield in cold regions.

Contribution of the Technical Efficiency of Public Health Programs to National Trends and Regional Disparities in Unintentional Childhood Injury in Japan.

To achieve the Sustainable Development Goals, strengthening investments in health service inputs has been widely emphasized, but less attention has been paid to tackling variation in the technical efficiency of services. In this study, we estimated the technical efficiency of local public health programs for the prevention of unintentional childhood injury and explored its contribution to national trend changes and regional health disparities in Japan. Efficiency scores were estimated based on the Cobb–Douglas and translog production functions using a true fixed effects model in a stochastic frontier analysis to account for unobserved time-invariant heterogeneity across prefectures. Using public data sources, we compiled panel data from 2001 to 2017 for all 47 prefectures in Japan. We treated disability-adjusted life years (DALYs) as the output, coverage rates of public health programs as inputs, and caregivers' capacity and environmental factors as constraints. To investigate the contribution of efficiency to trend changes and disparities in output, we calculated the predicted DALYs with several measures of inefficiency scores (2001 average, yearly average, and prefecture-year-specific estimates). In the translog model, mean efficiency increased from 0.62 in 2001 to 0.85 in 2017. The efficiency gaps among prefectures narrowed until 2007 and then remained constant until 2017. Holding inefficiency score constant, inputs and constraints contributed to improvements in average DALYs and widened regional gaps. Improved efficiency over the years further contributed to improvements in average DALYs. Efficiency improvement in low-output regions and stagnated improvement in high-output regions offset the trend of widening regional health disparities. Similar results were obtained with the Cobb–Douglas model. Our results demonstrated that assessing the inputs, constraints, output, and technical efficiency of public health programs could provide policy leverage relevant to region-specific conditions and performance to achieve health promotion and equity.