Applying Propensity Score Matching Research Articles

Impact of health insurance on healthcare utilisation patterns in Vietnam: a survey-based analysis with propensity score matching method

ObjectivesThe study aims to evaluate the impact of the Revised Health Insurance Law 2014 on the utilisation of outpatient and inpatient care services, healthcare services utilisation at different levels of...

Should I stay or should I go? Predictors and effects of studying abroad during high school

In an increasingly globalized and culturally diverse world, extended stays abroad during high school are considered important opportunities for acquiring and improving a variety of skills, most importantly, language achievement. This study examines both predictors and effects of studying abroad in an English-speaking country during high school, using population data from the second largest city in Germany (N = 5361; 13% went abroad). In order to determine the most central predictors of studying abroad, we employed logistic regression models in which students’ socioeconomic background emerged as the strongest predictor of studying abroad. To test the effects of studying abroad, we applied propensity score matching. Studying abroad had positive effects on standardized achievement, grades, and course choice in English, whereas it had hardly any effects on outcomes in math. Implications for studying abroad during high school and future research directions are discussed.

Radiomics-based nomogram using CT imaging for noninvasive preoperative prediction of early recurrence in patients with hepatocellular carcinoma.

The aim of this study was to develop and validate a radiomics nomogram based on radiomics features and clinical data for the non-invasive preoperative prediction of early recurrence (≤2 years) in patients with hepatocellular carcinoma (HCC). We enrolled 262 HCC patients who underwent preoperative contrast-enhanced computed tomography and curative resection (training cohort, n=214; validation cohort, n=48). We applied propensity score matching (PSM) to eliminate redundancy between clinical characteristics and image features, and the least absolute shrinkage and selection operator (LASSO) was used to prevent overfitting. Next, a radiomics signature, clinical nomogram, and combined clinical-radiomics nomogram were built to predict early recurrence, and we compared the performance and generalization of these models. The radiomics signature stratified patients into low-risk and high-risk, which show significantly difference in recurrence free survival and overall survival (P ≤ 0.01). Multivariable analysis identified dichotomised radiomics signature, alpha fetoprotein, and tumour number and size as key early recurrence indicators, which were incorporated into clinical and radiomics nomograms. The radiomics nomogram showed the highest area under the receiver operating characteristic curve (AUC), with significantly superior predictive performance over the clinical nomogram in the training cohort (0.800 vs 0.716, respectively; P = 0.001) and the validation cohort (0.785 vs 0.654, respectively; P = 0.039). The radiomics nomogram is a non-invasive preoperative biomarker for predicting early recurrence in patients with HCC. This model may be of clinical utility for guiding surveillance follow-ups and identifying optimal interventional strategies.

Job qualification programs for young apprentices: an analysis in the Brazilian Midwest

PurposeThe aim of this study is to evaluate five job qualification programs for young apprentices, in Goiás, a Brazilian State. We expect to contribute to the improvement and strengthening of the job training programs in developing countries.Design/methodology/approachWe applied propensity score matching and extensions such as the generalized propensity score method (dose–response effect).FindingsWe found evidence of the heterogenous effects of the five job qualification programs on employability. We found that the duration of the programs influences employability in up to two years after the program.Research limitations/implicationsThis research is based on secondary data provided by the responsible institutions. The evidence is obtained through a nonexperimental method.Practical implicationsThe research has implications for public or private institutions dedicated to the professional qualification of young apprentices.Social implicationsThe findings of the study provide some ways of comparing training programs, for young workers, that can be applied in different types of institutions.Originality/valueThis study provides new insight about the professional qualification of young apprentices, by comparing fives programs in Midwest Brazil.

Irrigation infrastructure and farm productivity in the Philippines: A stochastic Meta-Frontier analysis

Abstract Irrigation is a lynchpin of rural development strategies and a key input to improving productivity and farm incomes, the key source of livelihood for the majority of the world's poor. Limited land and growing water scarcity mean that establishing systems to maximise the benefits from every drop is pivotal. In this paper, we analyse the impact of a canal irrigation project for smallholders in the Philippines, focusing on rice, one of the world's most water intensive crops. We contribute to two strands of literature by combining impact evaluation and efficiency analysis methods. Using a dataset for 714 treatment and 440 control farm parcels, we apply Propensity Score Matching and a selectivity-corrected Stochastic Production Frontier to handle biases from both observable and unobservable variables. We then analyse technical efficiency (TE) and frontier output using a shared Stochastic Meta-Frontier. We find that the project had a statistically significant impact on frontier output but not on TE, suggesting that improved irrigation technology increased beneficiaries' production potential, but it did not improve TE likely due to insufficient training and input access. Thus, beneficiaries were unable to take full advantage of their improved production potential, highlighting the need for suitable complementary support in future projects. Heterogeneity analysis reveals that the main beneficiaries were downstream parcels, smaller parcels, those located in the poorer project district, and farmers with lower education, all implying a pro-poor impact. Finally, we find that female-headed households benefitted less from the project, suggesting the need for additional support in future interventions.

Does the origin matter? The effects of cross-border mergers and acquisitions in France

PurposeThe present article analyses the effects of cross-border mergers and acquisitions (CBM&As) on targets' total factor productivity (TFP), employment, wages and intangible-asset investment. The author investigates whether the impact of CBM&As differs depending on the origin of the investing multinational (MNE). The author distinguishes between CBM&As from European countries, other developed countries and emerging countries.Design/methodology/approachThe author makes use of a unique firm-level data set of foreign direct investment in the French manufacturing sector. The authors applies propensity score matching and difference in differences to estimate the effect of CBM&As.FindingsThe results show that the consequences of CBM&As differ strongly depending on the origin. CBM&As from European MNEs have a positive impact on TFP, wages and intangible-asset investment, and those from emerging countries seem to increase wages and intangible-asset investments. In contrast, CBM&As that originate from MNEs from other developed countries do not have a significant effect.Originality/valueThis article contributes to the growing literature on the effects of foreign direct investment that highlights the relevance of accounting for the MNEs' origin. In particular, it is the first to address the impact of emerging-country MNEs' CBM&As in Europe.

Visitation and Misconduct Among Maximum-Security Inmates

This study adds to the literature by clarifying the effects of visitation on serious and violent misconduct among maximum-security inmates through the application of propensity score matching (PSM). Findings demonstrate that once the visited and nonvisited groups were matched on covariates of visitation, major violations were significantly influenced by visitation from family and friends. The visitation group experienced a 25% reduction in major, violent, and injurious acts of misconduct. Results are discussed from the perspective of social support theory.

Education, Internet Use, and Confidence in the Police: Testing the “Informed Citizen” Thesis in the Philippines

We applied the “informed citizen” thesis to public confidence in the police in the Philippines—a topic that has surprisingly received little research attention. We analyzed four waves of survey data from the Asian Barometer Survey (ABS), and we applied propensity score matching (PSM) method and regression models to the data. We operationalized education, interest in politics, and Internet usage as indicators of an informed citizen. We tested whether they are predictive of confidence in the police. Confidence in the Philippine police has gradually improved from 2002 to 2014. Regression analysis found that citizens with more education and more Internet usage displayed lower levels of confidence in the Philippine police. We also found that an interaction effect between education and political interests, with education having a stronger connection to confidence in the police among those with greater political interests. Our findings support the informed citizen thesis and shed new light on the study of confidence in the Philippine police.

Association of prestroke metformin use, stroke severity, and thrombolysis outcome.

To evaluate whether pretreatment with metformin (MET) is associated with less stroke severity and better outcome after IV thrombolysis (IVT), we analyzed a cohort of 1,919 patients with stroke with type 2 diabetes mellitus in a multicenter exploratory analysis. Data from patients with diabetes and ischemic stroke treated with IVT were collected within the European Thrombolysis in Ischemic Stroke Patients (TRISP) collaboration. We applied propensity score matching (PSM) to obtain balanced baseline characteristics of patients treated with and without MET. Of 1,919 patients with stroke with type 2 diabetes who underwent IVT, 757 (39%) had received MET before stroke (MET+), whereas 1,162 (61%) had not (MET-). MET+ patients were younger with a male preponderance. Hypercholesterolemia and pretreatment with statins, antiplatelets, or antihypertensives were more common in the MET+ group. After PSM, the 2 groups were well balanced with respect to demographic and clinical aspects. Stroke severity on admission (NIH Stroke Scale 10.0 ± 6.7 vs 11.3 ± 6.5), 3-month degree of independence on modified Rankin Scale (2 [interquartile range (IQR) 1.0-4.0] vs 3 [IQR 1.0-4.0]), as well as mortality (12.5% vs 18%) were significantly lower in the MET+ group. The frequency of symptomatic intracerebral hemorrhages did not differ between groups. HbA1c levels were well-balanced between the groups. Patients with stroke and diabetes on treatment with MET receiving IVT had less severe strokes on admission and a better functional outcome at 3 months. This suggests a protective effect of MET resulting in less severe strokes as well as beneficial thrombolysis outcome.

Bipolar plasmakinetic transurethral enucleation and resection versus bipolar plasmakinetic transurethral resection for surgically treating large (≥60 g) prostates: a propensity score-matched analysis with a 3-year follow-up.

Background There are extremely limited published studies comparing bipolar plasmakinetic transurethral resection of prostate (BP-TURP) and bipolar plasmakinetic transurethral enucleation and resection of prostate (BP-TUERP) for enlarged prostates. Our purpose is to evaluate the safety and efficiency of BP-TUERP and BP-TURP for large (≥ 60 g) prostates with a 3-year follow-up. Methods We retrospectively identified 229 patients according to inclusion criteria between 2014 and 2016. After applying propensity score matching method, preoperative results and three-year follow-up outcomes in International Prostate Symptom Score (IPSS), urinary peek flow rate (Qmax), postvoid residual urine (PVRU) volume and quality of life (QoL) score were compared. Results Finally, within the well-balanced matched cohort, the BP-TUERP was significantly associated with longer mean operating time (OT) (p = 0.039), shorter mean catheter time (CT) (p = 0.001) and lower mean hemoglobin decrease (p = 0.002) with more prostatic tissue removed (p = 0.001) than the BP-TURP, but the median hospital stay lengths and the short- and long-term complication rates were similar between the two series. The patients in the BP-TUERP group had better long-term outcomes in IPSS, Qmax and PVRU volume than these in the BP-TURP group, but not in QoL score. Conclusions For patients with large (≥ 60 g) prostates, BP-TUERP and BP-TURP are safe options, but the former is a more effective choice in long-term follow-up outcomes. BP-TUERP is related to reduced CT and hemoglobin decrease with more removal of prostatic tissue at the expense of longer OT than BP-TURP.

Effect of the dynamic curve type from the perifocal infiltration zone obtained by magnetic resonance imaging on prognosis in pelvic pathologies in women

The aim of the study is to evaluate the role and prognostic significance of magnetic resonance imaging (MRI) perfusion methods in prognosis of disease course and outcome based on evaluation of the perifocal infiltration zone in pelvic disorders in women.Materials and methods. Retrospective analysis of pelvic MRI data obtained using MRI system with induced magnetic field of 1.5 T was performed. The study included 530 protocols of pelvic scans in women. Two equal groups (n = 265) of patients with oncological and nononcological pathologies of pelvic organs were formed; after application of propensity score matching, each group contained 165 patients. All examination protocols included dynamic contrast enhancement. The obtained data were statistically analyzed using the Stata 13 software.Results. In the study, types of dynamic curves obtained using dynamic contrast enhancement from the perifocal infiltration zone were analyzed. There was no data showing a correlation between the type of dynamic curve from the zone of perifocal changes and disease prognosis or possibility of differential diagnosis.Conclusions. Evaluation of the perifocal infiltration zone per MRI results with intravenous contrast does not affect prognostic accuracy of the method (p >0.05); contrast can be used only for differential diagnosis or evaluation of local advancement of the process.

Ten-year follow-up study of long-term outcomes after conservative surgery for early-stage ovarian cancer.

To evaluate long-term outcomes after surgery for apparent early-stage ovarian cancer (OC). Retrospective analysis of women who underwent staging surgery for apparent early-stage OC at a single center in Milan, Italy, from 1990 to 2008, and had a follow-up longer than 10years (living women with no recurrence). Univariate and multivariate analyses and propensity score matching were carried out. Overall, 182 women underwent radical (n=148, 81.3%) or conservative (n=34, 18.7%) procedures for early-stage OC. Ten-year disease-free and overall survival were 82.9% (n=151) and 87.9% (n=160), respectively. Conservative or radical surgery had similar disease-free (log-rank test, P=0.783) and overall (log-rank test, P=0.783) survival. These data were confirmed after the application of propensity score matching. High-risk features correlated with non-significant worse disease-free survival (P=0.080). In the high-risk group (≥Grade 3 or≥Stage IC), type of surgical approach (conservative vs radical) did not affect survival (hazard ratio, 0.81; 95% confidence interval, 0.18-3.56; P=0.781). Women with early-stage OC had encouraging long-term survival. The presence of high-risk disease had detrimental effects on survival, regardless of surgical approach. High-risk disease should not be considered a contraindication to conservative surgery.

Propensity score matching/reweighting analysis comparing intravenous golimumab to infliximab for ankylosing spondylitis using data from the GO-ALIVE and ASSERT trials

ObjectiveTo compare the relative efficacy of intravenous golimumab (GOL IV) and infliximab (IFX) for active ankylosing spondylitis (AS).MethodsPropensity score (PS) methods were used to compare the efficacy of GOL IV 2 mg/kg and IFX 5 mg/kg using individual patient data (IPD) from the active arms of the phase 3 GO-ALIVE and ASSERT studies. Outcomes included the proportion of patients with a ≥ 20% improvement in the Assessment of Spondyloarthritis International Society Criteria (ASAS20), change from baseline in Bath Ankylosing Spondylitis Functional Index (BASFI) score, and change from baseline in C-reactive protein (CRP) levels from weeks 4–52.ResultsBefore matching, 105 patients were treated with GOL IV and 201 patients were treated with IFX. After matching on all covariates, 118 patients were included in the ASAS20 analysis, 96 in the BASFI analysis, and 160 in the CRP analysis. After matching, GOL IV showed significantly greater improvement in ASAS20 response than IFX for weeks 28–44 (e.g., OR = 9.05 [95% CI 1.62–50.4] at week 44) and was comparable in change from baseline in BASFI scores and CRP levels to IFX at all time points. Results were robust for inclusion of different sets of covariates in scenario analyses.ConclusionsThis is the first analysis of its kind to leverage clinical trial data to compare two biologics using PS methods in the treatment of active AS. Overall, GOL IV was associated with greater improvement in ASAS20 response than IFX in patients with AS at 28, 36, and 44 weeks of follow-up.Key Points• Although intravenous golimumab (GOL IV) and infliximab (IFX) are the only two IV-based tumor necrosis factor (TNF) inhibitors with demonstrated phase 3 clinical efficacy in patients with ankylosing spondylitis (AS), no study has evaluated their comparative efficacy in a head-to-head trial.• Propensity score matching was used to derive indirect treatment comparisons of GOL IV and IFX for ≥ 20% in the Assessment of Spondyloarthritis International Society Criteria (ASAS20), change in Bath Ankylosing Spondylitis Functional Index (BASFI), and change in C-reactive protein (CRP) using individual patient data from the GO-ALIVE and ASSERT phase 3 trials.• Propensity score matched indirect comparisons showed improved relative efficacy of GOL IV compared to IFX; after matching for up to 16 baseline covariates, GOL IV was associated with significantly greater odds of ASAS20 response at weeks 28, 36, and 44 than IFX as well as equivalent changes from baseline in BASFI and CRP.• This novel application of propensity score matching using data from phase 3 trials, the first analysis of its kind in AS, allowed adjustment for important imbalances in prognostic factors between trials to generate estimates of comparative efficacy between GOL IV and IFX in the absence of a head-to-head trial between these treatments.

Forest commons, vertical integration and smallholder’s saving and investment responses: Evidence from a quasi-experiment

Abstract As the result of prohibitively high transaction costs, smallholder farmers are only partly integrated into agricultural and forest commodity markets, a situation that may leave them in a lower level of development equilibrium (i.e., a poverty trap). For the most part, many users of forest commons extract forest products, typically non-timber products, for subsistence use or safety net purposes. To overcome this problem, in recent years, collective vertical integration (VI) of forest product marketing cooperative structures have been promoted and, in some cases, adopted by users of forest commons. Although this type of program has been observed to raise smallholder incomes, there is little evidence available on saving/investment responses to such income gains. This paper investigates precautionary saving and investment responses to collective forest product marketing programs among users of forest commons in Ethiopian villages. To identify the causal effects of the program, I applied propensity score matching, difference-in-difference (DID) and change-in-change (CIC) estimators to household survey data collected from randomly selected households in the Gimbo district (south-western Ethiopia). I find strong evidence that participation in the program reduces savings in the form of livestock holdings and that effect is limited to non-poor households. When interpreted in terms of the Permanent Income Hypothesis (PIH), the results imply that participants felt the current income gains to be non-transient, which led to reduced precautionary savings and to a gain in consumption/welfare. Moreover, I found that the program has spurred investment in child education and participation in off-farm self-employment. These results point to the importance of the safety net/insurance channel of the program. Overall, the findings underscore the program’s potential to raise the standard of living via ancillary mechanisms beyond directly raising income outcome.

Post-privatization state ownership and bank risk-taking: Cross-country evidence

We examine the relation between state residual ownership and bank risk-taking for privatized banks from 45 countries. Applying propensity score matching, we find that privatized banks tend to exhibit higher levels of risk-taking post-privatization than their publicly listed non-privatized counterparts. Moreover, partially privatized banks exhibit higher levels of risk-taking than fully privatized banks. We also observe a positive and significant relation between the level of residual state ownership and risk-taking. These findings are consistent with the distorted objectives associated with government control, as suggested by the political benefits of control, and with the soft budget constraint views of state ownership. The distortion can be mitigated by the quality of a country's institutional and regulatory environments. Finally, our results show that the effect of state ownership on risk-taking is more pronounced in countries with a higher dominance of state-owned enterprises, and it was more prevalent during the global financial crisis.

Assessing the impact of a doctor in remote areas of Brazil.

The More Doctors Program (MDP) is an ongoing Brazilian policy that aims to improve healthcare by providing physicians to the most vulnerable municipalities. We aimed to measure the impact of MDP in mortality and infant mortality rate, the proportion of live births with low weight, prenatal appointments, childbirths at first and fifth min Apgar, public health investment and immunization in Brazil. Municipal health indicators were collected before and after the intervention (2012 and 2015). Effects were measured by applying propensity score matching with difference-in-differences. Our findings show that infant mortality presented the highest improvement during the period (a decrease in 11 infant deaths per 1000 live births, p < 0.01). A significant effect, albeit smaller, was also found for the age-standardized total mortality (a decrease in five deaths per 10,000 residents), proportion of children with Apgar score lower than 8 in the fifth min and children with low birth weight. MDP contributed to improve important health indicators, highlighting the importance of a doctor in remote areas of Brazil.

Drought Vulnerability and Child Mobility in Rural Senegal

Are children of rural households vulnerable to climate-related shocks more likely to live away from the parental household? What is the relationship between household drought shock vulnerability and child mobility, independent of factors such as poverty and traditional social practices? This article applies propensity score matching on household data from rural Senegal to address these questions. The results indicate a statistical association between households being drought-shocked and having at least one child living away of between 14 and 18 per cent, and of 13–19 per cent to having young boys who study the Quran away from home as so-called talibés.

Coste de las visitas médicas y urgencias asociadas al estrés laboral en España

Job stress is a serious problem for workers’ health, organizations and society. The aim of this paper is to assess the health care costs caused by the increase of health care services. Using the National Health Surveys (2006/07 and 2011/12), we have applied propensity score matching methods and microeconometric estimation in order to quantify the visits to general practitioner (GP), specialists and emergency visits due to job stress. In 2006/07 the assessment of these visits permits to conclude that the economic costs are 145.26 million € due to GP visits and emergency rooms. In 2011/12 the costs are 55.17 million € due to hospital emergencies.

Fair Trade and Wellbeing Improvements: Evidence from Sri Lanka

This paper investigates whether and how Fair Trade certification improves the wellbeing of small-scale producers by drawing upon a field study carried out by the authors in 2009 in the Central Province of Sri Lanka. A point of departure from earlier studies is to use a mixed methods approach, combining qualitative and quantitative data to assess the impact of Fair Trade on a broader set of development indicators to capture both the monetary and non-monetary progress of farmers. Methodologically, to overcome the limitation of small sample sizes of non-experimental survey data, we propose the use of propensity-score weighted linear and non-linear regression models with and without instrumenting the farmers’ participation in Fair Trade. Here we have made treatment and control groups observationally comparable by applying propensity score matching (PSM) to match and weight the data, following Hirano and Imbens. We have found that Fair Trade certification increased farmers’ actual income from tea production significantly, with fewer hours of work per day and accelerated perceived improvement in overall household income, as well as empowering women in decision making. Our mixed methods approach led us to conclude that Fair Trade certification benefits Fair Trade tea farmers through increased tea income and risk reduction.

Laparoscopic vs. Open Surgery for Stage II/III Colon Cancer Patients With Body Mass Index >25 kg/m2.

To compare long- and short-term outcomes of laparoscopic surgery with those of open surgery for patients with colorectal cancer and body mass index over 25 kg/m2 Patients and Methods: This multicentre, retrospective study analysed clinical records and identified 178 patients with body mass index over 25 kg/m2 who underwent surgery for colon and rectosigmoid cancer between 2000 and 2016. After applying propensity score matching, 96 patients were finally included. The primary outcome was the 3-year recurrence-free survival rate, and the secondary outcomes were short-term results during and after surgery. The 3-year recurrence-free survival rates were similar for the laparoscopic and open surgery groups. The laparoscopic surgery group had longer operative times but less blood loss and shorter periods of hospital stay. There were no differences in incidence of postoperative complications. Laparoscopic and open surgeries had similar long-term outcomes for obese patients. Laparoscopic surgery is an effective option for this population.