Applying Propensity Score Matching Research Articles

Effect of temozolomide on survival in elderly patients with glioblastoma and impaired performance status: a propensity score-matching analysis.

ObjectiveAt present, there is no consensus regarding the standard treatment for glioblastoma (GBM) in elderly patients with impaired Karnofsky performance status (KPS) scores. This study aimed to determine the effects of temozolomide (TMZ) versus best supportive care (BSC) in this population.Materials and methodsWe conducted a retrospective observational study of patients aged ≥65 years with histologically confirmed GBM and KPS scores ≤70 who were treated at our institution between January 2006 and July 2014. Demographic data, treatments, and outcomes were evaluated. Univariate and multivariate analyses were performed to identify the independent prognostic factors of overall survival (OS) and progression-free survival (PFS). The impact of TMZ on survival was analyzed by the application of propensity score matching of clinicopathological factors among patients who received TMZ vs BSC.ResultsThere were 153 patients (86 men, 56.2%) in this study. The median patient age was 70 years (range: 65–83 years). The median KPS score was 60 (range: 30–70). Seventy-eight patients (51.0%) received TMZ, whereas 75 (49.0%) received BSC. Median OS and PFS were 6.0 and 4.5 months, respectively. Compared with BSC, TMZ was associated with improved OS (hazard ratio [HR]: 0.38, 95% CI: 0.17–0.70; P=0.002) and PFS (HR: 0.41, 95% CI: 0.21–0.76; P=0.003) after propensity score matching. Factors independently associated with OS were KPS score (HR: 2.11, 95% CI: 1.48–7.67; P=0.016), extent of resection (HR: 1.98, 95% CI: 1.45–5.14; P=0.026), and treatment group (HR: 0.49, 95% CI: 0.23–0.87; P=0.019). The most frequent toxicity in the TMZ group was myelosuppression.ConclusionCompared with BSC, TMZ increased survival with acceptable toxicity in elderly GBM patients with KPS scores ≤70.

Estimating the impact of sericulture adoption on farmer income in Rwanda: an application of propensity score matching

ABSTRACTThe adoption of an agricultural technology is often seen as a way to overcome the constraints imposed by the existing resources and/or production methods. As a small landlocked country, Rwanda sought to develop the capability to produce silk, a high value-to-volume ratio product, as a means to overcome the constraints of high transportation cost of exports. Sericulture was also seen as a handy strategy to boost rural farmer income by putting previously less productive land to use for mulberry plantations. Because sericulture was not introduced randomly, this study relied on observational data and applied propensity score matching to estimate its income and poverty reduction effects in six rural districts. The results indicate that sericulture adoption had beneficial effects both on increasing income and reducing poverty. The strengthening of related skills development and the supporting infrastructure remains crucial for the sericulture to successfully diffuse and yield economic benefits commensurate with its potential.

Evaluation of the fiscal effect on municipal mergers: Quasi-experimental evidence from Japanese municipal data

The purpose of this paper is to evaluate a fiscal common pool problem in Japanese municipal mergers. Specifically, we investigate whether the merged municipalities rapidly increase their expenditures and bonds just before mergers. Because the likelihood of Japanese municipal mergers depends on a municipality's characteristics such as population size, area, and fiscal conditions, municipal mergers are a non-voluntary and non-random phenomenon in Japan. Therefore, we identify causal effects by applying propensity score matching within a differences-in-differences framework to address the problems of endogeneity bias and sample selection bias. In particular, we focus on the subordinate merger partner in absorption-type mergers. Our results show that the subordinate merger partner suffers from adverse fiscal conditions and creates a fiscal common pool problem in public projects just before mergers.

Remittances and Household Expenditure in Nepal: Evidence from Cross-Section Data

This paper examines the effect of remittances on household expenditure patterns applying propensity score matching methods that allow designing and analyzing observational data and enable reducing selection bias. We use data from the Nepal Living Standards Survey 2010/2011. In general, remittance recipient households tend to spend more on consumption, health and education as compared to remittance non-receiving households. Although the findings do not clearly provide evidence of either the productive or non-productive use of remittances, expenditures on non-food investment categories, such as durable goods, health and education, are more apparent among remittance-receiving households compared to remittance non-receiving households, which signal the prospect of a sustainable long-term welfare gain among the former.

Health system responsiveness and chronic disease care – What is the role of disease management programs? An analysis based on cross-sectional survey and administrative claims data

Health system responsiveness is an important aspect of health systems performance. The concept of responsiveness relates to the interpersonal and contextual aspects of health care. While disease management programs (DMPs) aim to improve the quality of health care (e.g. by improving the coordination of care), it has not been analyzed yet whether these programs improve the perceived health system responsiveness. Our study aims to close this gap by analyzing the differences in the perceived health system responsiveness between DMP-participants and non-participants.We used linked survey- and administrative claims data from 7037 patients with coronary heart disease in Germany. Of those, 5082 were enrolled and 1955 were not enrolled in the DMP.Responsiveness was assessed with an adapted version of the WHO responsiveness questionnaire in a postal survey in 2013. The survey covered 9 dimensions of responsiveness and included 17 items for each, GP and specialist care. Each item had five answer categories (very good – very bad). We handled missing values in the covariates by multiple imputation and applied propensity score matching (PSM) to control for differences between the two groups (DMP/non-DMP). We used Wilcoxon-signed-rank and McNemar test to analyze differences regarding the reported responsiveness.The PSM led to a matched and well balanced sample of 1921 pairs. Overall, DMP-participants rated the responsiveness of care more positive. The main difference was found for the coordination of care at the GP, with 62.0% of 1703 non-participants reporting a “good” or “very good” experience, compared to 69.1% of 1703 participants (p < 0.001).The results of our study indicate an overall high responsiveness for CHD-care, as well for DMP-participants as for non-participants. Yet, the results also clearly indicate that there is still a need to improve the coordination of care.

Risk and timing of clinical events according to diabetic status of patients treated with everolimus‐eluting bioresorbable vascular scaffolds versus everolimus‐eluting stent: 2‐year results from a propensity score matched comparison of ABSORB EXTEND and SPIRIT trials

to compare the occurrence of clinical events in diabetics treated with the Absorb bioresorbable vascular scaffold (Absorb BVS; Abbott Vascular, Santa Clara, CA) versus everolimus-eluting metal stents (EES; XIENCE V; Abbott Vascular, Santa Clara, CA) BACKGROUND: There are limited data dedicated to clinical outcomes of diabetic patients treated with bioresorbable scaffolds (BRS) at 2-year horizon. The present study included 812 patients in the ABSORB EXTEND study in which a total of 215 diabetic patients were treated with Absorb BVS. In addition, 882 diabetic patients treated with EES in pooled data from the SPIRIT clinical program (SPIRIT II, SPIRIT III and SPIRIT IV trials) were used for comparison by applying propensity score matching using 29 different variables. The primary endpoint was ischemia driven major adverse cardiac events (ID-MACE), including cardiac death, myocardial infarction (MI), and ischemia driven target lesion revascularization (ID-TLR). After 2 years, the ID-MACE rate was 6.5% in the Absorb BVS vs. 8.9% in the Xience group (P = 0.40). There was no difference for MACE components or definite/probable device thrombosis (HR: 1.43 [0.24,8.58]; P = 0.69). The occurrence of MACE was not different for both diabetic status (insulin- and non-insulin-requiring diabetes) in all time points up to the 2-year follow-up for the Absorb and Xience groups. In this largest ever patient-level pooled comparison on the treatment of diabetic patients with BRS out to two years, individuals with diabetes treated with the Absorb BVS had a similar rate of MACE as compared with diabetics treated with the Xience EES. © 2017 Wiley Periodicals, Inc.

Are There Gender Differences in Professional Self-Promotion? An Empirical Case Study of LinkedIn Profiles Among Recent MBA Graduates

Women are more modest than men in expressing accomplishments, referred to as the “feminine modesty effect”. Given the importance of highlighting accomplishments and skills for professional advancement, our research revisits the classical question of equal opportunity with a modern dataset to examine how women leverage LinkedIn, a professional social networking site. We first apply propensity score matching methods to identify a subset of similarly qualified female and male U.S. users who recently graduated/will be graduating (2011-2017) from a top-ranked MBA program as indicated on their LinkedIn profile. We then analyze gender differences in online self-promotion choices, an often overlooked aspect of understanding the role of gender in the professional hiring pipeline. Among matched subsets of female and male users, we find that females are less likely relative to males to utilize data fields that require writing in free-form such as the Summary and Job Description fields. However, we find for most universities that females and males are equally likely to include more structured data fields such as Honors and Skills, and for some universities females are more likely to include at least one Skill. This work begins to quantify gender biases in user-provided data and introduces important considerations for how self-presentation choices affect professional opportunity in online hiring platforms.

Microfinance beyond self-employment: Evidence for firms in Bulgaria

This paper provides new evidence on the impact of microfinance on job creation beyond self-employment. We examine wage-employment effects for a typical program in Eastern Europe with average loan sizes that are considerably above what has been studied so far. We apply propensity score matching extended by a difference-in-differences estimator to panel data from an individual-lending program to firms in Bulgaria. Our results indicate that microcredit has very positive effects on job creation. Participating firms have on average 2.5 (or 33 percent) more employees two years after receiving a microcredit than matched non-participants. This strong effect seems to be related to a certain loan size threshold necessary for positive impacts to unfold. Effects are largest for the smallest firms, supporting findings from other studies that small firms are more constrained by credit than large firms. Investigating dynamic effects for up to six years after treatment, we furthermore show that effects are long lasting.

Effectiveness of triple therapy with direct-acting antivirals for hepatitis C genotype 1 infection: application of propensity score matching in a national HCV treatment registry

BackgroundObservational studies are used to measure the effectiveness of an intervention in non-experimental, real world scenarios at the population level and are recognised as an important component of the evidence pyramid. Such data can be accrued through prospective cohort studies and a patient registry is a proven method for this type of study. The national hepatitis C (HCV) registry was established in Ireland in 2012 with the aim of monitoring the clinical and economic outcomes from new, high cost regimens for the treatment of HCV infection. A sustained virological response (SVR) 24 weeks following completion of therapy with interferon-containing regimens is considered a cure. Non-randomisation in these studies can result in confounding or selection bias. Propensity score (PS) matching is one of a number of statistical tools that can be used to mitigate the effects of confounding in observational studies.MethodsWe analysed the data of 309 patients who underwent triple therapy treatment with telaprevir (TPV) in combination with pegylated-interferon and ribavirin (PR) or boceprevir (BOC)/PR between June 2012 and December 2014. The decision to initiate treatment and the selection of the treatment regimen was at the discretion of the physician. To adjust for confounding, three approaches to propensity score matching were assessed Adjusted sustained-virological response rates (SVR), odds ratios, p-values and 95% confidence intervals were calculated from the three PS matched dataset.ResultsPrior to matching, the unadjusted sustained virological response rates 24 weeks after treatment complete (SVR24) were 74% (n = 158/215) and 61% (n = 57/94) for telaprevir/PR and boceprevir/PR, respectively. After matching, adjusted SVR24 rates were between 73–74% and 60–61% for telaprevir/PR and boceprevir/PR, respectively.ConclusionEfficacy rates were comparable with those reported in pivotal clinical trials and real world studies. After adjusting for confounding, we conclude that there was no difference in treatment effect after PS matching. The small sample size limits the conclusions that can be made about the effect of PS matching. Propensity score adjustment remains a tool that can be applied to future analysis, however, we suggest, where possible, using a larger sample size in order to reduce the uncertainty around the outcomes.

Economic crisis and the unemployment effect on household food expenditure: The case of Spain

This paper examines the unemployment effect on food expenditure (UEFE) for Spanish households and quantifies its magnitude in boom and crisis periods. The results show that the UEFE was negative in both contexts but was reinforced during the economic crisis. Applying propensity score matching and difference-in-differences techniques to a sample of Spanish households for 2006 and 2013 (representative of a boom period and a crisis period, respectively), we found that the UEFE amounted to 2.9% in the boom period and to 4.5% in the crisis period. Quantile difference-in-differences estimates confirmed that the economic crisis enhanced the UEFE for Spanish households, with this effect decreasing continuously up to quantile 0.9. The UEFE was exacerbated mainly in those economically disadvantaged households.

Mortality Risk after Diagnosis of Early-Onset Alzheimer's Disease versus Late-Onset Alzheimer's Disease: A Propensity Score Matching Analysis.

We aimed to compare the risk of mortality in patients with early-onset Alzheimer's disease (EOAD) versus those with late-onset AD (LOAD) using a large number of study subjects. We applied propensity score matching (PSM) to minimize confounding biases in the comparison between EOAD and LOAD. We obtained data from elderly Korean subjects with AD (n = 3,611) at baseline from the CREDOS cohort study, which was conducted from November 2005 to July 2013. We conducted PSM to reduce the bias due to confounding variables related to survival in patients with AD. The risks of mortality associated with EOAD and LOAD were evaluated by Cox proportional hazard analyses, controlling for relevant covariates. After propensity score matching, 312 subjects with EOAD and 624 subjects with LOAD were selected for further analysis. The Cox proportional hazard analysis showed that patients with EOAD are at a greater risk for mortality compared to those with LOAD (Hazard Ratio: 2.01, 95% CI: 1.01-4.00, p-value: 0.04) when controlling for the direct effect of aging on mortality. The results did not change after adjusting for age at diagnosis, general cognitive function, nutritional factor related to body mass index, and physical disability using activities of daily living. The results support the assumption that EOAD takes a more malignant course than LOAD. Our results provide support for the idea that EOAD takes a clinical course that is distinct from that of LOAD, especially as pertains to the risk of mortality.

How do Tertiary Dropouts Fare in the Labour Market? A Comparison between EU Countries

AbstractDropping out of university is regularly discussed as a negative indicator. However, research on actual career trajectories of dropouts is virtually non‐existent. This study estimates the association between tertiary dropouts and career chances in 15 European countries. Using data from the 2011 Programme for the International Assessment of Adult Competencies (PIAAC), estimates are derived from the application of propensity score matching taking a variety of individual background characteristics including cognitive skills into account. Results indicate that individuals are likely to fare better in the labour market if they enrol in university and drop out than if they do not enrol at all. Policy makers need to revise the notion that dropping out is purely negative.

Ration Balancing: Promising Option for Doubling Income from Dairying

This paper has examined the extent of productivity increase and cost reduction on adoption of balanced animal ration. The study is based on the database extracted from Information Network for Animal Productivity and Health (INAPH) pertaining to the milk yield and feeding records of about 15000 cattle and buffaloes that were covered under Ration Balancing Program (RBP) of the National Dairy Plan I implemented in the states of Gujarat and Punjab. The econometric analysis of secondary data following before-after impact assessment approach has also been complemented using with-without approach applying Propensity Score Matching technique on the data from field survey collected from 40 villages during the year 2015–16. In Gujarat, the analysis has shown that the ration balancing intervention enhanced the productivity of cows by around 13 per cent and of buffaloes by nearly 5.5 per cent. The quantum of increase discernible from the with-without approach after controlling for the confounding factors was higher, 19.5 per cent for cows and 18 per cent for buffaloes. In Punjab, the estimates of productivity gain for cows was close to 13 per cent based on either approach. Ration balancing has been cost effective in terms of percentage reduction in feed cost and feed cost/litre Fat Corrected Milk (FCM) of both, cattle and buffalo, with the cost efficiency being more pronounced in cows. In cattle, the feed cost per litre FCM reduced in between 5.76 and 9.86 per cent in Gujarat and by 10.83–18.53 per cent in Punjab. The field level data have also indicated a clear impact in reducing the feed cost per litre of milk by about 18–19 per cent in case of cows in both the states and about 2.6 per cent in buffaloes in Gujarat. Given the potential of this intervention in enhancing the dairy income, the paper has also discussed various ways in which its adoption can be promoted among the dairy farmers.

Impact of Land Use Rights Transfer on Household Labor Productivity: A Study Applying Propensity Score Matching in Chongqing, China

In order to improve the rural labor productivity and farmers’ income, land use transfer was launched and encouraged in recent years, especially the Thirteenth Five-Year Plan (2016–2020). This study aims to shed light on the impact of land use rights transfer on household labor productivity, based on a case study of Chongqing in China. Studies have revealed that land use transfer entails a process of self-selection and does not occur in a random manner. The study, therefore, addressed the issue of sample selection by applying propensity score matching. The study results suggested significant differences in the effects of land use transfer on household labor productivity. Specifically, renting land from other households had a positive effect on total labor productivity (TLP) and agricultural labor productivity (ALP). Moreover, TLP and ALP were found to be higher for households that rented more land or that were located in plain areas. Renting out land had a robust and positive effect on the TLP and non-agricultural labor productivity (NALP). TLP and NALP were also higher for households that rented out more land or that were located in plain areas. These findings suggest that land use transfer should be actively encouraged in plain areas. However, in mountainous areas, there is a need to pay more attention to expanding agriculture to benefit poor and marginalized populations in these areas.

Continued export trade, screening-matching and gender discrimination in employment

The screening mechanism of export trade facilitates enterprises to increase their recruitment threshold, which in turn has a biased impact on the employment of heterogeneous individuals. Incorporating export trade, screening-matching and gender discrimination in employment into a unified analysis and applying propensity score matching estimation on the basis of the theoretical framework of micro-enterprise and the optimized behavior of job seekers, this paper examines the relations between export trade of industrial enterprises and female labor employment levels in China during 2005–2007. The results indicate that: (1) the number and ration of female employees are increasing with the size and growth of the enterprise export, regardless of enterprise exports continuity. It demonstrates that export expansion does play a critical role in mitigating gender discrimination in employment. (2) For the enterprise with higher export continuity, there is a significant effect toward improving the number and proportion of female employees, conversely the worse effect. Thus, it is significantly meaningful to mitigate gender discrimination in employment by ensuring the continued export capacity of enterprises. (3) Comparing to the promoting effect of growth in the number of female employees, export has limit effect up on increasing the proportion of female employees. Therefore, it is rather difficult to resolve the issue of gender discrimination in employment by relying completely on exports expansion. Based on research findings, this paper discusses the policy implications in terms of easing gender discrimination in employment and promoting employment equity.

Sudden gains in routine care cognitive behavioral therapy for depression: A replication with extensions

BackgroundOver the last decade, a substantial amount of findings have been reported on the association between sudden gains (large symptom improvements in a between-session interval) and treatment outcome. Accurate replications of previous findings are needed to tackle inconsistencies and to shed light on the clinical implications of sudden gains. This study investigates whether similar effects of sudden gains can be expected under routine care conditions, when the patients are comparable to those examined in the original study by Tang and DeRubeis (1999). MethodUsing propensity score matching (PSM), 462 patients treated with cognitive behavioral therapy (CBT) under routine conditions were matched stepwise to patients of the original study on sudden gains, a randomized controlled CBT trial (RCT). ResultsAfter the application of PSM, the effects of sudden gains on treatment outcome were similar to those found by Tang and DeRubeis (1999). The closer the match between the RCT and the naturalistic sample, the more similar the association between sudden gains and treatment outcome. ConclusionSudden gains seem to have a significant impact on recovery rates, even in treatments under routine care. Results suggest that one important aspect of replication success is to control for confounding baseline covariates.

The impact of fiscal rules on sovereign risk premia: International evidence

We examine whether adopting a numerical fiscal rule framework to guide fiscal policy helps reduce sovereign risk premia in a sample of advanced and developing countries for 1985–2012. We address the self-selection problem of policy adoption by applying propensity score matching methods. The results suggest that adopting fiscal rules reduces sovereign risk premia.

Who Buffers Income Losses after Job Displacement? The Role of Alternative Income Sources, the Family, and the State

Using survey data from the German Socio-Economic Panel (SOEP) this paper analyses to what extent alternative income sources, reactions within the household context, and redistribution by the state attenuate earnings losses after job displacement. Applying propensity score matching and fixed effects estimations, we find high individual earnings losses after job displacement and only limited convergence. Income from self-employment slightly reduces the earnings gap and severance payments buffer losses in the short run. On the household level, we find substantial and rather persistent losses in per capita labour income. We do not find that increased labour supply by other household members contributes to the compensation of the income losses. Most importantly, our results show that redistribution within the tax and transfer system substantially mitigates income losses of displaced workers both in the short and the long run whereas other channels contribute only little.

Outside Directors and Firm Performance During Institutional Transitions: New Evidence from Dissenting Opinions

Prior studies examine outside directors’ characteristics without considering their behaviors and document mixed results. We propose a new measure based on dissenting opinions expressed by outside directors in board meetings, which provide unique insights into their active monitoring actions. We use the data to examine their role in the context of rapidly evolving institutional transitions in China and in the light of the methodological implications of the endogeneity problem of the relevant literature. After addressing the problem by applying propensity score matching, we find that neither board independence nor dissenting opinions alone improve firm performance. However, as per our predictions drawn from agency and power circulation theories, their joint effect significantly improves firm performance in that board independence empowers active outside directors to discipline managers.

Unintended Childbearing and Child Growth in Northern Malawi

Objective The study aims to assess whether unintended children experience slower growth than intended children. Methods We analysed longitudinal data linked to the Karonga Health and Demographic Surveillance Site collected over three rounds between 2008 and 2011 on women’s fertility intentions and anthropometric data of children. Using the prospective information on fertility intention we assessed whether unintended children are more likely to be stunted than intended children. We applied Propensity Score Matching technique to control for endogenous factors affecting both the probability that a family has an unwanted birth and a child with poor health outcomes. Results We found that 24 % of children from unwanted pregnancies were stunted compared with 18 % of mistimed pregnancies and 17 % of those from wanted pregnancies. However, these differences in probability of children being stunted, though in the expected direction, were not significant either for large or small families, after controlling for age. The number of children in the household was associated with stunting and boys were substantially more likely to be stunted than girls. Conclusion We found no significance difference in probability of being stunted by mother’s fertility intention.