The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Haresh Kirpalani - One of the best experts on this subject based on the ideXlab platform.
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Survival rates in extremely low birthweight infants depend on the Denominator: avoiding potential for bias by specifying Denominators.
American journal of obstetrics and gynecology, 2011Co-Authors: Ursula Guillen, Sara Demauro, John Zupancic, Eileen Wang, Amiram Gafni, Haresh KirpalaniAbstract:The objective of the study was to assess whether recent data reporting survival of preterm infants introduce a bias from the use of varying Denominators. We performed a systematic review of hospital survival of infants less than 1000 g or less than 28 weeks. Included publications specified the Denominator used to calculate survival rates. Of 111 eligible publications only 51 (46%) specified the Denominators used to calculate survival rates: 6 used all births, 25 used live births, and 20 used neonatal intensive care unit admissions. Overall rates of survival to hospital discharge ranged widely: from 26.5% to 87.8%. Mean survival varied significantly by Denominator: 45.0% (±11.6) using a Denominator of all births, 60.7% (±13.2) using live births, or 71.6% (±12.1) using used neonatal intensive care unit admissions (P ≤ .009 or less for each of 3 comparisons). Variations in reported rates of survival to discharge for extremely low-birthweight (<1000 g) and extremely low-gestational-age (<28 weeks) infants reflect in part a Denominator bias that dramatically affects reported data. Copyright © 2011 Mosby, Inc. All rights reserved.
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Survival rates in extremely low birthweight infants depend on the Denominator: avoiding potential for bias by specifying Denominators.
American Journal of Obstetrics and Gynecology, 2011Co-Authors: Ursula Guillen, Sara Demauro, Eileen Wang, Amiram Gafni, John A.f. Zupancic, Haresh KirpalaniAbstract:Objective The objective of the study was to assess whether recent data reporting survival of preterm infants introduce a bias from the use of varying Denominators. Study Design We performed a systematic review of hospital survival of infants less than 1000 g or less than 28 weeks. Included publications specified the Denominator used to calculate survival rates. Results Of 111 eligible publications only 51 (46%) specified the Denominators used to calculate survival rates: 6 used all births, 25 used live births, and 20 used neonatal intensive care unit admissions. Overall rates of survival to hospital discharge ranged widely: from 26.5% to 87.8%. Mean survival varied significantly by Denominator: 45.0% (±11.6) using a Denominator of all births, 60.7% (±13.2) using live births, or 71.6% (±12.1) using used neonatal intensive care unit admissions (P ≤ .009 or less for each of 3 comparisons). Conclusion Variations in reported rates of survival to discharge for extremely low-birthweight (
Thomas Zaslavsky - One of the best experts on this subject based on the ideXlab platform.
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A $q$-Queens Problem. IV. Attacking Configurations and Their Denominators
Discrete Mathematics, 2020Co-Authors: Seth Chaiken, Christopher R. H. Hanusa, Thomas ZaslavskyAbstract:Abstract In Parts I–III we showed that the number of ways to place q nonattacking queens or similar chess pieces on an n × n chessboard is a quasipolynomial function of n whose coefficients are essentially polynomials in q . In this part we focus on the periods of those quasipolynomials. We calculate Denominators of vertices of the inside-out polytope, since the period is bounded by, and conjecturally equal to, their least common Denominator. We find an exact formula for that Denominator of every piece with one move and of two-move pieces having a horizontal move. For pieces with three or more moves, we produce geometrical constructions related to the Fibonacci numbers that show the Denominator grows at least exponentially with q .
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A $q$-Queens Problem. IV. Attacking Configurations and Their Denominators
arXiv: Combinatorics, 2018Co-Authors: Seth Chaiken, Christopher R. H. Hanusa, Thomas ZaslavskyAbstract:In Parts I-III we showed that the number of ways to place $q$ nonattacking queens or similar chess pieces on an $n\times n$ chessboard is a quasipolynomial function of $n$ whose coefficients are essentially polynomials in $q$. In this part we focus on the periods of those quasipolynomials. We calculate Denominators of vertices of the inside-out polytope, since the period is bounded by, and conjecturally equal to, their least common Denominator. We find an exact formula for that Denominator of every piece with one move and of two-move pieces having a horizontal move. For pieces with three or more moves, we produce geometrical constructions related to the Fibonacci numbers that show the Denominator grows at least exponentially with $q$.
Megan E. Vanneman - One of the best experts on this subject based on the ideXlab platform.
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Are Improvements in Measured Performance Driven by Better Treatment or "Denominator Management"?
Journal of General Internal Medicine, 2016Co-Authors: Alex H. S. Harris, Cheng Chen, Anna D. Rubinsky, Katherine J. Hoggatt, Matthew J. Neuman, Megan E. VannemanAbstract:BACKGROUND Process measures of healthcare quality are usually formulated as the number of patients who receive evidence-based treatment (numerator) divided by the number of patients in the target population (Denominator). When the systems being evaluated can influence which patients are included in the Denominator, it is reasonable to wonder if improvements in measured quality are driven by expanding numerators or contracting Denominators.
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are improvements in measured performance driven by better treatment or Denominator management
Journal of General Internal Medicine, 2016Co-Authors: Alex H. S. Harris, Cheng Chen, Anna D. Rubinsky, Katherine J. Hoggatt, Megan E. Vanneman, Matthew NeumanAbstract:BACKGROUND Process measures of healthcare quality are usually formulated as the number of patients who receive evidence-based treatment (numerator) divided by the number of patients in the target population (Denominator). When the systems being evaluated can influence which patients are included in the Denominator, it is reasonable to wonder if improvements in measured quality are driven by expanding numerators or contracting Denominators.
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Are Improvements in Measured Performance Driven by Better Treatment or "Denominator Management"?
Journal of general internal medicine, 2016Co-Authors: Alex H. S. Harris, Cheng Chen, Anna D. Rubinsky, Katherine J. Hoggatt, Matthew Neuman, Megan E. VannemanAbstract:Process measures of healthcare quality are usually formulated as the number of patients who receive evidence-based treatment (numerator) divided by the number of patients in the target population (Denominator). When the systems being evaluated can influence which patients are included in the Denominator, it is reasonable to wonder if improvements in measured quality are driven by expanding numerators or contracting Denominators. In 2003, the US Department of Veteran Affairs (VA) based executive compensation in part on performance on a substance use disorder (SUD) continuity-of-care quality measure. The first goal of this study was to evaluate if implementing the measure in this way resulted in expected improvements in measured performance. The second goal was to examine if the proportion of patients with SUD who qualified for the Denominator contracted after the quality measure was implemented, and to describe the facility-level variation in and correlates of Denominator contraction or expansion. Using 40 quarters of data straddling the implementation of the performance measure, an interrupted time series design was used to evaluate changes in two outcomes. All veterans with an SUD diagnosis in all VA facilities from fiscal year 2000 to 2009. The two outcomes were 1) measured performance-patients retained/patients qualified and 2) Denominator prevalence-patients qualified/patients with SUD program contact. Measured performance improved over time (P < 0.001). Notably, the proportion of patients with SUD program contact who qualified for the Denominator decreased more rapidly after the measure was implemented (p = 0.02). Facilities with higher pre-implementation Denominator prevalence had steeper declines in Denominator prevalence after implementation (p < 0.001). These results should motivate the development of measures that are less vulnerable to Denominator management, and also the exploration of "shadow measures" to monitor and reduce undesirable Denominator management.
Matthias Troyer - One of the best experts on this subject based on the ideXlab platform.
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Subband Engineering Even-Denominator Quantum Hall States
Physical Review B, 2010Co-Authors: Vito W. Scarola, Christian May, Michael R. Peterson, Matthias TroyerAbstract:Proposed even-Denominator fractional quantum Hall effect (FQHE) states suggest the possibility of excitations with non-Abelian braid statistics. Recent experiments on wide square quantum wells observe even-Denominator FQHE even under electrostatic tilt. We theoretically analyze these structures and develop a procedure to accurately test proposed quantum Hall wavefunctions. We find that tilted wells favor partial subband polarization to yield Abelian even-Denominator states. Our results show that tilting quantum wells effectively engineers different interaction potentials allowing exploration of a wide variety of even-Denominator states.
Ursula Guillen - One of the best experts on this subject based on the ideXlab platform.
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Survival rates in extremely low birthweight infants depend on the Denominator: avoiding potential for bias by specifying Denominators.
American journal of obstetrics and gynecology, 2011Co-Authors: Ursula Guillen, Sara Demauro, John Zupancic, Eileen Wang, Amiram Gafni, Haresh KirpalaniAbstract:The objective of the study was to assess whether recent data reporting survival of preterm infants introduce a bias from the use of varying Denominators. We performed a systematic review of hospital survival of infants less than 1000 g or less than 28 weeks. Included publications specified the Denominator used to calculate survival rates. Of 111 eligible publications only 51 (46%) specified the Denominators used to calculate survival rates: 6 used all births, 25 used live births, and 20 used neonatal intensive care unit admissions. Overall rates of survival to hospital discharge ranged widely: from 26.5% to 87.8%. Mean survival varied significantly by Denominator: 45.0% (±11.6) using a Denominator of all births, 60.7% (±13.2) using live births, or 71.6% (±12.1) using used neonatal intensive care unit admissions (P ≤ .009 or less for each of 3 comparisons). Variations in reported rates of survival to discharge for extremely low-birthweight (<1000 g) and extremely low-gestational-age (<28 weeks) infants reflect in part a Denominator bias that dramatically affects reported data. Copyright © 2011 Mosby, Inc. All rights reserved.
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Survival rates in extremely low birthweight infants depend on the Denominator: avoiding potential for bias by specifying Denominators.
American Journal of Obstetrics and Gynecology, 2011Co-Authors: Ursula Guillen, Sara Demauro, Eileen Wang, Amiram Gafni, John A.f. Zupancic, Haresh KirpalaniAbstract:Objective The objective of the study was to assess whether recent data reporting survival of preterm infants introduce a bias from the use of varying Denominators. Study Design We performed a systematic review of hospital survival of infants less than 1000 g or less than 28 weeks. Included publications specified the Denominator used to calculate survival rates. Results Of 111 eligible publications only 51 (46%) specified the Denominators used to calculate survival rates: 6 used all births, 25 used live births, and 20 used neonatal intensive care unit admissions. Overall rates of survival to hospital discharge ranged widely: from 26.5% to 87.8%. Mean survival varied significantly by Denominator: 45.0% (±11.6) using a Denominator of all births, 60.7% (±13.2) using live births, or 71.6% (±12.1) using used neonatal intensive care unit admissions (P ≤ .009 or less for each of 3 comparisons). Conclusion Variations in reported rates of survival to discharge for extremely low-birthweight (
