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Methodological Biases (methodological + biase)

Distribution by Scientific Domains

Life Sciences	40%
Business, Economics, Finance and Accounting	40%

Selected Abstracts

Potential Errors in Detecting Earnings Management: Reexamining Studies Investigating the AMT of 1986,

CONTEMPORARY ACCOUNTING RESEARCH, Issue 4 2001
Won W. Choi
Abstract In this paper we seek to document errors that could affect studies of earnings management. The book income adjustment (BIA) of the alternative minimum tax (AMT) created apparently strong incentives to manage book income downward in 1987. Five earlier papers using different methodologies and samples all conclude that earnings were reduced in response to the BIA. This consensus of findings offers an opportunity to investigate our speculation that methodological biases are more likely when there appear to be clear incentives for earnings management. A reexamination of these studies uncovers potential biases related to a variety of factors, including choices of scaling variables, selection of affected and control samples, and measurement error in estimated discretionary accruals. A reexamination of the argument underlying these studies also suggests that the incentives to manage earnings are less powerful than initially predicted, and are partially mitigated by tax and non-tax factors. As a result, we believe that the extent of earnings management that occurred in 1987 in response to the BIA remains an unresolved issue. [source]

Impacts of land use change on South-east Asian forest butterflies: a review

JOURNAL OF APPLIED ECOLOGY, Issue 4 2007
LIAN PIN KOH
Summary 1South-east Asia has the highest relative rate of habitat loss and degradation in the humid tropics. The responses of less ,charismatic' groups, including butterflies, to habitat disturbance remain relatively poorly understood. Many South-east Asian butterflies are endemic to the region and face global extinction if current levels of deforestation were to continue. 2Here, I highlight South-east Asia as a region urgently in need of butterfly conservation research and review empirical studies of the responses of South-east Asian butterflies to land use change. Additionally, I discuss some methodological pitfalls for such studies. Furthermore, I argue for the importance of identifying the ecological correlates of sensitivity of butterfly species to forest modification and the potential biological mechanisms underlying their responses to land use change. 3There has been no consensus among previous studies on the effects of land use change on butterfly communities in South-east Asia. Of the 20 studies I reviewed, seven reported higher species richness/diversity in undisturbed (or the least disturbed) forest than in disturbed habitats, nine reported the opposite trend, three reported no difference and one reported a strong influence of seasonality on the impacts of logging. 4Some of these studies may contain inherent methodological biases resulting from the failure to control for sampling effects, the lack of consideration for the spatial scale of analysis and incomplete sampling of the vertical strata in tropical rainforests. 5Synthesis and applications. Empirical studies of the effects of land use change on tropical forest insects are sorely lacking from South-east Asia. Butterflies are an ideal taxonomic group for such investigations. Future studies should be designed carefully to avoid the methodological pitfalls highlighted here. Determining the ecological correlates of sensitivity of butterflies to forest modification is important for the pre-emptive identification of species of conservation concern and for generating testable hypotheses on the differential responses of species to forest modification. Experimental studies are needed to determine the mechanisms underlying the responses of species to land use change in order to develop effective strategies for the conservation of butterflies in human disturbed landscapes. [source]

The poverty of economic explanations of consumption and an action theory alternative

MANAGERIAL AND DECISION ECONOMICS, Issue 3-4 2000
Richard P BagozziArticle first published online: 27 MAR 200
The purpose of this essay is to critique economic conceptualizations of consumer behaviour and explanations of consumer choice, and to propose an alternative rooted in the philosophy of mind and action, as well as in nascent social psychological and marketing models of purposive behaviour. It is claimed that economic theory harbours ideological and methodological biases in how consumer behaviour is conceived and obscures understanding of the many decision processes constituting consumer behaviour and its causes and effects. A novel multistage model is proposed to account for consumer goal achievement/goal failure, where goal outcomes are hypothesized to be joint functions of consumer actions and physical, social, or other environmental forces. Consumer action, in turn, is proposed to begin with reasoning processes (subject to nonconscious biases found in neural operations), to undergo appraisals of anticipated goal outcomes, which are experienced as positive and negative emotions, to involve a subsequent integrative stage of desire production, where reasoning, emotional, and social processes are integrated and transformed into a decision to act or not, and finally to encompass additional affective and reasoning processes that are initiated in a stage termed, ,trying to consume', wherein decisions are planned and implemented, and goal-directed behaviours activated. Copyright © 2000 John Wiley & Sons, Ltd. [source]

Pharmacogenetics of Immunosuppressants: Progress, Pitfalls and Promises

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 7 2008
D. Cattaneo
Most of the immunosuppressants used in organ transplantation are characterized by a narrow therapeutic index, whereby underdosing is associated with increased risk of rejection episodes and overdosing may exacerbate drug-related toxicity. Pharmacogenetics,complementary to pharmacokinetics,holds the potential to allow individualized dosing of immunosuppressive agents to optimize their therapeutic actions while minimizing adverse effects. Most of the studies have focused on polymorphisms of genes involved in drug metabolism and distribution, but as of now, only thiopurine-S-methyltransferase and cytochrome P 450 3A5 genotypes appear to have sufficiently large influence to have potentialities in guiding drug dosing. This may reflect the fact that available information from other polymorphisms derives almost exclusively from retrospective observations or from studies with important methodological biases. Active investigations aimed at identifying allelic variants of gene encoding for the pharmacologic targets are now ongoing. Recent studies have demonstrated that also donor genotype may play a significant role in immunosuppressive drug pharmacokinetics and pharmacodynamics. As one of the main future tasks, it is mandatory to develop mathematical models able to incorporate multiple gene polymorphisms with pharmacokinetic data and other critical information, providing algorithms able to individualize the best immunosuppressive therapy for each patient before transplantation. [source]

Sensitivity analysis of different methods of coding taxonomic polymorphism: an example from higher-level bat phylogeny

CLADISTICS, Issue 6 2002
Nancy B. Simmons
New information concerning strengths and weaknesses of different methods of coding taxonomic polymorphisms suggests that results of some previous studies may have been unintentionally biased by the methods employed. In this study, we demonstrate that a form of sensitivity analysis can be used to evaluate the effects of different methods of coding taxonomic polymorphisms on the outcome of phylogenetic analyses. Our earlier analysis of higher-level relationships of bats (Mammalia: Chiroptera) employed superspecific taxa as terminals and scored taxonomic polymorphisms using ambiguity coding. Application of other methods of dealing with polymorphisms (excluding variable characters, inferring ancestral states, majority coding) to the same data yields phylogenetic results that differ somewhat from those originally reported based on ambiguity coding. Monophyly of some clades was supported in all analyses (e.g., Microchiroptera, Rhinopomatoidea, and Nataloidea), while other groups found to be monophyletic in the original study (e.g., neotropical Nataloidea) appeared unresolved or nonmonophyletic when other methods were used to code taxonomic polymorphisms. Several groupings that were apparently refuted in the initial study (e.g., Noctilionoidea including Mystacinidae) were supported in some analyses, reducing some of the apparent incongruence between the trees in our earlier analysis (which were based principally on morphology) and other trees based on molecular data. Perceived support for various groupings (branch support, bootstrap values) were in some cases significantly affected by the methods employed. These results indicate that sensitivity analysis provides a useful tool for evaluating effects of different methods of dealing with taxonomic polymorphism in superspecific terminal taxa. Variation in results obtained with different methods suggests that it is always preferable to sample at the species level when higher-level taxa exhibit taxonomic polymorphism, thus avoiding methodological biases associated with different methods of dealing with taxonomic polymorphisms during data analysis. [source]