scispace - formally typeset
Search or ask a question
Author

Lawrence D. Phillips

Bio: Lawrence D. Phillips is an academic researcher from London School of Economics and Political Science. The author has contributed to research in topics: Decision analysis & Medicine. The author has an hindex of 33, co-authored 142 publications receiving 9337 citations. Previous affiliations of Lawrence D. Phillips include Imperial College London & Brunel University London.


Papers
More filters
Book ChapterDOI
01 Jun 1981
TL;DR: In this paper, a review of the literature concerning calibration of probabilistic assessments is presented, where the authors identify two kinds of "goodness" in probability assessments: normative goodness, which reflects the degree to which assessments express the assessor's true beliefs and conform to the axioms of probability theory, and substantive goodness, reflecting the amount of knowledge of the topic area contained in the assessments.
Abstract: From the subjectivist point of view (de Finetti, 1937/1964), a probability is a degree of belief in a proposition. It expresses a purely internal state; there is no “right,” “correct,” or “objective” probability residing somewhere “in reality” against which one's degree of belief can be compared. In many circumstances, however, it may become possible to verify the truth or falsity of the proposition to which a probability was attached. Today, one assesses the probability of the proposition “it will rain tomorrow.” Tomorrow, one looks at the rain gauge to see whether or not it has rained. When possible, such verification can be used to determine the adequacy of probability assessments. Winkler and Murphy (1968b) have identified two kinds of “goodness” in probability assessments: normative goodness, which reflects the degree to which assessments express the assessor's true beliefs and conform to the axioms of probability theory, and substantive goodness, which reflects the amount of knowledge of the topic area contained in the assessments. This chapter reviews the literature concerning yet another aspect of goodness, called calibration. If a person assesses the probability of a proposition being true as .7 and later finds that the proposition is false, that in itself does not invalidate the assessment. However, if a judge assigns .7 to 10,000 independent propositions, only 25 of which subsequently are found to be true, there is something wrong with these assessments.

1,829 citations

Journal ArticleDOI
TL;DR: Improved scoring and weighting approach of MCDA increases the differentiation between the most and least harmful drugs, however, the findings correlate poorly with present UK drug classification, which is not based simply on considerations of harm.

1,298 citations

Journal ArticleDOI
TL;DR: Estimates were most nearly Bayesian under the (formally inappropriate) linear payoff, but considerable overestimation resulted; the log payoff condition yielded less conservatism than the quadratic payoff and when Ss estimated odds on a logarithmic scale.
Abstract: 3 experiments investigated the effects on posterior probability estimates of: (1) prior probabilities, amount of data, and diagnostic impact of the data; (2) payoffs; and (3) response modes. Ss usually behaved conservatively, i.e., the difference between their prior and posterior probability estimates was less than that prescribed by Bayes' theorem. Conservatism was unaffected by prior probabilities, remained constant as the amount of data increased, and decreased as the diagnostic value of each datum decreased. More learning occurred under payoff than under nonpayoff conditions and between-S variance was less under payoff conditions. Estimates were most nearly Bayesian under the (formally inappropriate) linear payoff, but considerable overestimation resulted; the log payoff condition yielded less conservatism than the quadratic payoff. Estimates were most nearly Bayesian when Ss estimated odds on a logarithmic scale.

729 citations

Book ChapterDOI
01 Jan 1977
TL;DR: From the subjectivist point of view (de Finetti, 1937) a probability is a degree of belief in a proposition whose truth has not been ascertained and there is no “right” or “correct” probability that resides somewhere “in reality” against which it can be compared.
Abstract: From the subjectivist point of view (de Finetti, 1937) a probability is a degree of belief in a proposition whose truth has not been ascertained. A probability expresses a purely internal state; there is no “right” or “correct” probability that resides somewhere “in reality” against which it can be compared. However, in many circumstances, it may become possible to verify the truth o£ falsity of the proposition to which a probability was attached. Today, we assess the probability of the proposition“it will rain tomorrow”. Tomorrow, we go outside and look at the rain gauge to see whether or not it has rained. When verification is possible, we can use it to gauge the adequacy of our probability assessments.

665 citations

Posted Content
TL;DR: The copyright in the typographical arrangement rests with the Crown as discussed by the authors, and the material must be acknowledged as Crown copyright and the title of the publication specified, and must be reproduced accurately and not used in a misleading context.
Abstract: Copyright in the typographical arrangement rests with the Crown. This publication, excluding logos, may be reproduced free of charge in any format or medium for research, private study or for internal circulation within an organisation. This is subject to it being reproduced accurately and not used in a misleading context. The material must be acknowledged as Crown copyright and the title of the publication specified.

550 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: In this article, the authors focus on the linkages between the industry analysis framework, the resource-based view of the firm, behavioral decision biases and organizational implementation issues, and connect the concept of Strategic Industry Factors at the market level with the notion of Strategic Assets at the firm level.
Abstract: We build on an emerging strategy literature that views the firm as a bundle of resources and capabilities, and examine conditions that contribute to the realization of sustainable economic rents. Because of (1) resource-market imperfections and (2) discretionary managerial decisions about resource development and deployment, we expect firms to differ (in and out of equilibrium) in the resources and capabilities they control. This asymmetry in turn can be a source of sustainable economic rent. The paper focuses on the linkages between the industry analysis framework, the resource-based view of the firm, behavioral decision biases and organizational implementation issues. It connects the concept of Strategic Industry Factors at the market level with the notion of Strategic Assets at the firm level. Organizational rent is shown to stem from imperfect and discretionary decisions to develop and deploy selected resources and capabilities, made by boundedly rational managers facing high uncertainty, complexity, and intrafirm conflict.

8,121 citations

Book
24 Aug 2012
TL;DR: This textbook offers a comprehensive and self-contained introduction to the field of machine learning, based on a unified, probabilistic approach, and is suitable for upper-level undergraduates with an introductory-level college math background and beginning graduate students.
Abstract: Today's Web-enabled deluge of electronic data calls for automated methods of data analysis. Machine learning provides these, developing methods that can automatically detect patterns in data and then use the uncovered patterns to predict future data. This textbook offers a comprehensive and self-contained introduction to the field of machine learning, based on a unified, probabilistic approach. The coverage combines breadth and depth, offering necessary background material on such topics as probability, optimization, and linear algebra as well as discussion of recent developments in the field, including conditional random fields, L1 regularization, and deep learning. The book is written in an informal, accessible style, complete with pseudo-code for the most important algorithms. All topics are copiously illustrated with color images and worked examples drawn from such application domains as biology, text processing, computer vision, and robotics. Rather than providing a cookbook of different heuristic methods, the book stresses a principled model-based approach, often using the language of graphical models to specify models in a concise and intuitive way. Almost all the models described have been implemented in a MATLAB software package--PMTK (probabilistic modeling toolkit)--that is freely available online. The book is suitable for upper-level undergraduates with an introductory-level college math background and beginning graduate students.

8,059 citations

Journal ArticleDOI
TL;DR: Across 4 studies, the authors found that participants scoring in the bottom quartile on tests of humor, grammar, and logic grossly overestimated their test performance and ability.
Abstract: People tend to hold overly favorable views of their abilities in many social and intellectual domains. The authors suggest that this overestimation occurs, in part, because people who are unskilled in these domains suffer a dual burden: Not only do these people reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the metacognitive ability to realize it. Across 4 studies, the authors found that participants scoring in the bottom quartile on tests of humor, grammar, and logic grossly overestimated their test performance and ability. Although their test scores put them in the 12th percentile, they estimated themselves to be in the 62nd. Several analyses linked this miscalibration to deficits in metacognitive skill, or the capacity to distinguish accuracy from error. Paradoxically, improving the skills of participants, and thus increasing their metacognitive competence, helped them recognize the limitations of their abilities.

5,376 citations

Journal ArticleDOI
TL;DR: Confirmation bias, as the term is typically used in the psychological literature, connotes the seeking or interpreting of evidence in ways that are partial to existing beliefs, expectations, or a h...
Abstract: Confirmation bias, as the term is typically used in the psychological literature, connotes the seeking or interpreting of evidence in ways that are partial to existing beliefs, expectations, or a h...

5,214 citations

Journal ArticleDOI
TL;DR: A review of the literature on quality assessment of medical care can be found in this article, where the authors focus almost exclusively on the evaluation of the medical care process at the level of physician-patient interaction.
Abstract: This p aper i s a n a ttempt t o d escribe a nd evaluate current methods for assessing the quality of medical care and to suggest some directions for further study. It is concerned with methods rather than findings, and with an evaluation of methodology in general, rather than a detailed critique of methods in specific studies. This is not an exhaustive review of the pertinent literature. Certain key studies, of course, have been included. Other papers have been selected only as illustrative examples. Those omitted are not, for that reason, less worthy of note. This paper deals almost exclusively with the evaluation of the medical care process at the level of physician-patient interaction. It excludes, therefore, processes primarily related to the effective delivery of medical care at the community level. Moreover, this paper is not concerned with the administrative aspects of quality control. Many of the studies reviewed here have arisen out of the urgent need to evaluate and control the quality of care in organized programs of medical care. Nevertheless, these studies will be discussed only in terms of their contribution to methods of assessment and not in terms of their broader social goals. The author has remained, by and large, in the familiar territory of care provided by physicians and has avoided incursions into other types of

5,020 citations