acknowledged as are the comments and feedback we have received from the experimental economics community. Any opinions, findings, and conclusions or recommendations in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation

Other Regarding Preferences: A Selective Survey of Experimental Results

This monograph reviews the econometric literature on the estimation of stochastic frontiers and technical efficiency. Special attention is devoted to current research.

/pdf/efficiency-analysis-a-primer-on-recent-advances-7kq5pd5f8r.pdf

Efficiency Analysis: A Primer on Recent Advances

A rich theory of production and analysis of productive eciency has developed since pioneering work by Koopmans (1951) and Debreu (1951). Farrell (1957) is the earliest published empirical study, and appeared in a statistical journal (JRSS), even though Farrell provided no statistical theory. The literature in econometrics, management sciences, operations research and mathematical statistics has since been enriched by hundreds of papers trying to develop or implement new tools for analyzing productivity and efficiency of firms. Both parametric and nonparametric approaches have been proposed. The mathematical challenge is to derive estimators of production, cost, revenue,or profit frontiers which represent, in the case of production frontiers, the optimal loci of combinations of inputs (like labor, energy, capital, etc.) and outputs (the products or services produced by the firms). Optimality is defined in terms of various economic considerations. Then the efficiency of a particular unit is measured by its distance to the estimated frontier. The statistical problem can be viewed as the problem of estimating the support of a multivariate random variable, subject to some shape constraints, in multiple dimensions. These techniques are applied in thousands of papers in the economic and business literature. This "Guided Tour" reviews the development of various nonparametric approaches since the early work of Farrell. Remaining challenges and open issues in this challenging arena are also described.

/pdf/statistical-approaches-for-nonparametric-frontier-models-a-2c307766wq.pdf

Statistical Approaches for Nonparametric Frontier Models: A Guided Tour

Understanding the effects of operational conditions and practices on productive efficiency can provide valuable economic and managerial insights. The conventional approach is to use a two-stage method where the efficiency estimates are regressed on contextual variables representing the operational conditions. The main problem of the two-stage approach is that it ignores the correlations between inputs and contextual variables. To address this shortcoming, we build on the recently developed regression interpretation of data envelopment analysis (DEA) to develop a new one-stage semi-nonparametric estimator that combines the nonparametric DEA-style frontier with a regression model of the contextual variables. The new method is referred to as stochastic semi-nonparametric envelopment of z variables data (StoNEZD). The StoNEZD estimator for the contextual variables is shown to be statistically consistent under less restrictive assumptions than those required by the two-stage DEA estimator. Further, the StoNEZD estimator is shown to be unbiased, asymptotically efficient, asymptotically normally distributed, and converge at the standard parametric rate of order n
 −1/2. Therefore, the conventional methods of statistical testing and confidence intervals apply for asymptotic inference. Finite sample performance of the proposed estimators is examined through Monte Carlo simulations.

One-stage estimation of the effects of operational conditions and practices on productive performance: asymptotically normal and efficient, root-n consistent StoNEZD method

Estimating the shadow prices of SO2 and NOx for U.S. coal power plants: A convex nonparametric least squares approach

Data Envelopment Analysis (DEA) is a Mathematical Programming technique that finds a number of applications to measure the performance of similar units. The performance of these units say Decision Making Units (DMU) is assessed with DEA is obtained by using the concept of Efficiency which is the ratio of Weighted Sum of outputs to weighted sum of inputs. The efficiency obtained by using DEA are relative to best performance of Virtual DMU. In the present study, the efficiency of Production has been measured by specifying and estimating the parameters of Translog output distance function. Further, a non-parametric approach has been applied to measure the efficiency of production by constructing several Linear Programming Problem based on Translog output distance function to study efficiency variation in Indian Commercial Banks.

Efficiency Estimation of Production Functions

Background: The prevalence of major coronal and sagittal spinal curves (scoliosis and kyphosis) in Turner syndrome (TS) is not well established due to limited reporting. The relationship between growth hormone (GH) therapy and its effect on TS spinal curve incidence is also not well established. Methods: A retrospective chart review of 306 TS patients from 2007 to 2021 evaluated major coronal and sagittal spinal curves, progression of the curve, and treatment with GH. Statistical significance (defined as P <0.05) between curvature rates and curve progression was compared between GH-treated patients and non–GH-treated patients using a χ2 or Fisher exact test when appropriate. Results: Thirty-seven of 306 (12%) TS patients had a radiographically relevant spinal deformity. Twenty-seven of 37 (73%) had mild; 4 of 37 (11%) had moderate, and 6 of 37 (16%) had severe curves. Of those with severe, 4 underwent spinal fusion, 1 was treated with bracing, and 1 was braced before a cardiovascular-related death. Regarding GH use among TS patients, 190 of 306 (62%) used GH versus 116 of 306 (38%) who did not. Of those with a spinal curve, 24 of 37 (65%) used GH compared with 13 of 37 (35%) who did not. On univariate analysis, GH therapy was not a risk factor for the diagnosis of a major spinal curve, a more severe degree of the curve at the time of diagnosis, or spinal curve progression (P >0.05 for all). Conclusions: This is the largest single institution retrospective review of a TS cohort known to the authors assessing spinal curve prevalence and relation to GH treatment and demonstrates a TS spinal curve rate of 12% (37/306). Four of six (11%) TS patients with a severe curve underwent corrective spine fusion. There was no relationship between the use of GH and the presence of a spinal curve or curve progression. Further study is warranted to determine risk factors for curve progression. Level of Evidence: Level III. Clinical Relevance: This retrospective case series serves to review and address the prevalence of spinal deformity in TS patients and whether GH impacts worsening deformity.

Scoliosis and Kyphosis Prevalence in Turner Syndrome: A Retrospective Review at a Pediatric Tertiary Care Medical Center

http://www.heartrhythmjournal.com/article/S1547527123011748/pdf

Po-02-109 facilitating left bundle branch pacing by identifying the tip of the triangle of koch with right atrial septogram

The prevalence and treatment of severe scoliosis and other spinal anomalies in patients with Turner's syndrome (TS) is not well reported. This is the largest case series to date regarding the treatment course and outcomes of severely scoliotic TS patients. A retrospective chart review was performed to identify all patients with TS seen at a single center academic pediatric institution from 2007 to 2021. Of these, the presence of concomitant severe scoliosis or other spinal anomalies was determined, defined by a major coronal curve measuring 45° or greater. Demographic, clinical, surgical, and radiologic data was collected at both pre- and post-intervention time points. A retrospective chart review identified 306 patients with TS. Of those, six were identified to have severe scoliosis or other severe spinal anomalies requiring fusion. All four posterior spinal fusion (PSF) patients demonstrated improvement of their spinal curvature. One patient who electively pursued only bracing demonstrated minimal improvement and surgery was subsequently recommended, but not pursued. One patient expired from a pre-existing heart condition prior to intervention. All postoperative complications resolved with no further complications. The only brace-related complication was an allergic rash related to the brace material. All four patients who underwent PSF demonstrated significant improvement of their spinal curvature with few post-surgical complications. None of the patients in the bracing cohort demonstrated stabilization of their spinal curvature. Therefore, these data corroborate with prior studies, suggesting that operative management consisting of spinal fusion with instrumentation provides optimal clinical outcomes, compared to bracing only. 

Management of severe scoliosis in patients with Turner's syndrome: A case series.

OBJECTIVE
The aim of this study was to summarize the prognosis of recurrent infratentorial ependymomas based on treatment and molecular characterization.


METHODS
Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the authors searched the PubMed, Scopus, Embase, and Ovid databases for studies on recurrent infratentorial ependymomas in patients younger than 25 years of age. Exclusion criteria included case series of fewer than 5 patients and studies that did not provide time-dependent survival data.


RESULTS
The authors' database search yielded 482 unique articles, of which 18 were included in the final analysis. There were 479 recurrent infratentorial pediatric ependymomas reported; 53.4% were WHO grade II and 46.6% were WHO grade III tumors. The overall mortality for recurrent infratentorial pediatric ependymomas was 49.1% (226/460). The pooled mean survival was 30.2 months after recurrence (95% CI 22.4-38.0 months). Gross-total resection (GTR) was achieved in 243 (59.0%) patients at initial presentation. The mean survival postrecurrence for those who received initial GTR was 42.3 months (95% CI 35.7-47.6 months) versus 26.0 months (95% CI 9.6-44.6 months) for those who received subtotal resection (STR) (p = 0.032). There was no difference in the mean survival between patients who received GTR (49.3 months, 95% CI 32.3-66.3 months) versus those who received STR (41.4 months, 95% CI 11.6-71.2 months) for their recurrent tumor (p = 0.610). In the studies that included molecular classification data, there were 169 (83.3%) posterior fossa group A (PFA) tumors and 34 (16.7%) posterior fossa group B (PFB) tumors, with 28 tumors harboring a 1q gain. PFA tumors demonstrated worse mean postprogression patient survival (24.7 months, 95% CI 15.3-34.0 months) compared with PFB tumors (48.0 months, 95% CI 32.8-63.2 months) (p = 0.0073). The average postrecurrence survival for patients with 1q+ tumors was 14.7 months.


CONCLUSIONS
The overall mortality rate for recurrent infratentorial ependymomas was found to be 49.1%, with a pooled mean survival of 30.2 months in the included sample population. More than 80% of recurrent infratentorial ependymomas were of the PFA molecular subtype, and both PFA tumors and those with 1q gain demonstrated worse prognosis after recurrence.

M.Venkataramanaiah Balasiddamuni Pagadala

Papers

Efficiency Estimation of Production Functions

Scoliosis and Kyphosis Prevalence in Turner Syndrome: A Retrospective Review at a Pediatric Tertiary Care Medical Center

Po-02-109 facilitating left bundle branch pacing by identifying the tip of the triangle of koch with right atrial septogram

Management of severe scoliosis in patients with Turner's syndrome: A case series.

Recurrent pediatric infratentorial ependymomas: a systematic review and meta-analysis on outcomes and molecular classification.