44 research outputs found
The role of experience in common sense and expert problem solving
Issued as Progress reports [nos. 1-5], Reports [nos. 1-6], and Final report, Project no. G-36-617 (includes Projects nos. GIT-ICS-87/26, GIT-ICS-85/19, and GIT-ICS-85/18
State space models of remote manipulation tasks.
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1968.Vita.Bibliography: leaves 188-190.Ph.D
Economic analysis in health care regulation: three essays
ABSTRACT - It is the purpose of the present thesis to emphasize, through a series of examples, the need and
value of appropriate pre-analysis of the impact of health care regulation. Specifically, the thesis
presents three papers on the theme of regulation in different aspects of health care provision
and financing. The first two consist of economic analyses of the impact of health care regulation
and the third comprises the creation of an instrument for supporting economic analysis of
health care regulation, namely in the field of evaluation of health care programs.
The first paper develops a model of health plan competition and pricing in order to understand
the dynamics of health plan entry and exit in the presence of switching costs and alternative
health premium payment systems. We build an explicit model of death spirals, in which profitmaximizing
competing health plans find it optimal to adopt a pattern of increasing relative
prices culminating in health plan exit. We find the steady-state numerical solution for the price
sequence and the plan’s optimal length of life through simulation and do some comparative
statics. This allows us to show that using risk adjusted premiums and imposing price floors are
effective at reducing death spirals and switching costs, while having employees pay a fixed
share of the premium enhances death spirals and increases switching costs.
Price regulation of pharmaceuticals is one of the cost control measures adopted by the
Portuguese government, as in many European countries. When such regulation decreases the
products’ real price over time, it may create an incentive for product turnover.
Using panel data for the period of 1997 through 2003 on drug packages sold in Portuguese
pharmacies, the second paper addresses the question of whether price control policies create
an incentive for product withdrawal. Our work builds the product survival literature by
accounting for unobservable product characteristics and heterogeneity among consumers when
constructing quality, price control and competition indexes. These indexes are then used as
covariates in a Cox proportional hazard model. We find that, indeed, price control measures
increase the probability of exit, and that such effect is not verified in OTC market where no such
price regulation measures exist. We also find quality to have a significant positive impact on
product survival.
In the third paper, we develop a microsimulation discrete events model (MSDEM) for costeffectiveness
analysis of Human Immunodeficiency Virus treatment, simulating individual paths
from antiretroviral therapy (ART) initiation to death. Four driving forces determine the course
of events: CD4+ cell count, viral load resistance and adherence. A novel feature of the model with respect to the previous MSDEMs is that distributions of time to event depend on
individuals’ characteristics and past history. Time to event was modeled using parametric
survival analysis. Events modeled include: viral suppression, regimen switch due virological
failure, regimen switch due to other reasons, resistance development, hospitalization, AIDS
events, and death. Disease progression is structured according to therapy lines and the model is
parameterized with cohort Portuguese observational data.
An application of the model is presented comparing the cost-effectiveness ART initiation with
two nucleoside analogue reverse transcriptase inhibitors (NRTI) plus one non-nucleoside
reverse transcriptase inhibitor(NNRTI) to two NRTI plus boosted protease inhibitor (PI/r) in HIV-
1 infected individuals. We find 2NRTI+NNRTI to be a dominant strategy. Results predicted by
the model reproduce those of the data used for parameterization and are in line with those
published in the literature
Fourth Annual Workshop on Space Operations Applications and Research (SOAR 90)
The proceedings of the SOAR workshop are presented. The technical areas included are as follows: Automation and Robotics; Environmental Interactions; Human Factors; Intelligent Systems; and Life Sciences. NASA and Air Force programmatic overviews and panel sessions were also held in each technical area