Showing papers by "McMaster University published in 1991"
TL;DR: In this article, a process dissociation procedure is proposed to separate the contributions of different types of processes to performance of a task, rather than equating processes with tasks, by separating automatic from intentional forms of processing.
3,557 citations
TL;DR: Telomere length and telomerase activity appear to be markers of the replicative history and proliferative potential of cells; the intriguing possibility remains that telomere loss is a genetic time bomb and hence causally involved in cell senescence and immortalization.
Abstract: The Holy Grail of gerontologists investigating cellular senescence is the mechanism responsible for the finite proliferative capacity of somatic cells. In 1973, Olovnikov proposed that cells lose a small amount of DNA following each round of replication due to the inability of DNA polymerase to fully replicate chromosome ends (telomeres) and that eventually a critical deletion causes cell death. Recent observations showing that telomeres of human somatic cells act as a mitotic clock, shortening with age both in vitro and in vivo in a replication dependent manner, support this theory's premise. In addition, since telomeres stabilize chromosome ends against recombination, their loss could explain the increased frequency of dicentric chromosomes observed in late passage (senescent) fibroblasts and provide a checkpoint for regulated cell cycle exit. Sperm telomeres are longer than somatic telomeres and are maintained with age, suggesting that germ line cells may express telomerase, the ribonucleoprotein enzyme known to maintain telomere length in immortal unicellular eukaryotes. As predicted, telomerase activity has been found in immortal, transformed human cells and tumour cell lines, but not in normal somatic cells. Telomerase activation may be a late, obligate event in immortalization since many transformed cells and tumour tissues have critically short telomeres. Thus, telomere length and telomerase activity appear to be markers of the replicative history and proliferative potential of cells; the intriguing possibility remains that telomere loss is a genetic time bomb and hence causally involved in cell senescence and immortalization.
1,186 citations
TL;DR: Using this method of statistical data compression a multivariate monitoring procedure analogous to the univariate Shewart Chart has been developed to efficiently monitor the performance of large processes, and to rapidly detect and identify important process changes.
Abstract: Process computers routinely collect hundreds to thousands of pieces of data from a multitude of plant sensors every few seconds. This has caused a “data overload” and due to the lack of appropriate analyses very little is currently being done to utilize this wealth of information. Operating personnel typically use only a few variables to monitor the plant's performance. However, multivariate statistical methods such as PLS (Partial Least Squares or Projection to Latent Structures) and PCA (Principal Component Analysis) are capable of compressing the information down into low dimensional spaces which retain most of the information. Using this method of statistical data compression a multivariate monitoring procedure analogous to the univariate Shewart Chart has been developed to efficiently monitor the performance of large processes, and to rapidly detect and identify important process changes. This procedure is demonstrated using simulations of two processes, a fluidized bed reactor and an extractive distillation column.
966 citations
TL;DR: The human adenoviruses, particularly types 2, 5, and 12, have been the most extensively characterized, and these viruses have served as valuable tools in the study of the molecular biology of DNA replication, transcription, RNA processing, and protein synthesis in mammalian cells.
Abstract: Adenoviruses have been isolated from a large number of different species (mammalian and fowl) and over 100 different serotypes have been reported, some 43 of them human. The human adenoviruses, particularly types 2, 5, and 12, have been the most extensively characterized, and these viruses have served as valuable tools in the study of the molecular biology of DNA replication, transcription, RNA processing, and protein synthesis in mammalian cells. Seeref. 1 for a general review.
883 citations
TL;DR: In this paper, a review of applications of corona discharge induced plasmas and unipolar ions is presented, focusing on one of two aspects of the discharge: the ions produced or the energetic electrons producing the plasma.
Abstract: Applications of corona discharge induced plasmas and unipolar ions are reviewed. Corona process applications emphasize one of two aspects of the discharge: the ions produced or the energetic electrons producing the plasma. The ion identities depend on the polarity of the discharge and the characteristics of the gas mixture, specifically on the electron attaching species. The electron energies depend on the gas characteristics and on the method of generating the corona. In general, in an application using ions, the corona induced plasma zone will occupy a small fraction of the total process volume, while a process using the electrons will fill most of the volume with the plasma. Current state-of-the knowledge of ionized environments and the function of corona discharge processes are discussed in detail. >
820 citations
TL;DR: The OQAQ is a valid measure of the quality of research overviews and the primary shortcoming noted was the need for judgement in applying the index.
798 citations
TL;DR: The RQLQ is likely to prove useful as a measure of health‐related quality of life in clinical trials in both rhinoconjunctivitis and rhinitis.
Abstract: The objective of this study was to develop and test a health-related quality of life questionnaire for clinical trials in rhinoconjunctivitis. The Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) was developed by asking patients to identify areas of their lives affected by rhinoconjunctivitis. The resultant RQLQ was tested for reproducibility, responsiveness and validity in a randomized, double-blind trial of regular versus 'as required' aqueous beclomethasone dipropionate (BDP) nasal spray in ragweed pollen-induced rhinoconjunctivitis. Eighty-five patients from previous rhinoconjunctivitis studies participated in the developmental survey. Sixty ragweed-sensitive patients, from previous trials and media notices, were enrolled in the clinical trial. Aqueous BDP (800 micrograms) nasal spray was administered regularly or 'as required' throughout the ragweed pollen season. The survey revealed that, in addition to local symptoms of rhinoconjunctivitis, patients experienced impairment of quality of life through systemic symptoms, sleep disturbance, practical problems, activity limitations and emotional problems. The RQLQ includes 28 questions related to these dimensions. Repeated administration of the RQLQ demonstrated good reproducibility. During the clinical trial, the RQLQ proved responsive in its ability to distinguish between regular and 'as required' medication use. Validity was shown by moderate to strong relations between changes in symptom diary scores and changes in RQLQ scores. In conclusion the RQLQ is likely to prove useful as a measure of health-related quality of life in clinical trials in both rhinoconjunctivitis and rhinitis.
740 citations
TL;DR: After 24 months the trial of labor and vaginal birth rates in the audit and feedback group were no different from those in the control group, but rates were 46% and 85% higher, respectively, among physicians educated by an opinion leader.
Abstract: A randomized controlled trial with 76 physicians in 16 community hospitals evaluated audit and feedback and local opinion leader education as methods of encouraging compliance with a guideline for the management of women with a previous cesarean section. The guideline recommended clinical actions to increase trial of labor and vaginal birth rates. Charts for all 3552 cases in the study groups were audited. After 24 months the trial of labor and vaginal birth rates in the audit and feedback group were no different from those in the control group, but rates were 46% and 85% higher, respectively, among physicians educated by an opinion leader. Duration of hospital stay was lower in the opinion leader education group than in the other two groups. The overall cesarean section rate was reduced only in the opinion leader education group. There were no adverse clinical outcomes attributable to the interventions. The use of opinion leaders improved the quality of care. ( JAMA . 1991;265:2202-2207)
696 citations
TL;DR: This paper surveys the literature related to optimal maintenance and replacement models for multi-unit systems and provides a quick guide to a variety of classification schemes.
687 citations
TL;DR: Tests of the reliability and validity of the Calgary Depression Scale concluded that the CDS is a parsimonious reliable scale which is suitable for assessing depression across both the acute and residual stages of schizophrenia.
TL;DR: Although the improved reliability of the Standardized Mini-Mental State was achieved by reducing measurement noise, this advantage would likely occur in a broad spectrum of patients.
Abstract: Objective The objective of this study was to compare the reliability of the Mini-Mental State Examination with that of a new Standardized Mini-Mental State Examination, which has expanded guidelines for administration and scoring. Method The subjects were 32 stable elderly residents of a nursing home and 16 elderly residents of a chronic care hospital unit. Six raters administered the Folstein Mini-Mental State to 22 of these stable elderly subjects, and five raters administered the standardized version to 26 of these subjects. Each subject was tested on three different occasions 1 week apart. Each rater tested 4-6 subjects at the first and third weeks and 4-6 different subjects at the second week. The analytic technique used was one-way analysis of variance to estimate the interrater variance and the intrarater variance. Results The intrarater variance on all occasions was reduced by 86% and the interrater variance was reduced by 76% when the Standardized Mini-Mental State was used; the reductions in variance were significant (p less than 0.003). The intraclass correlation for the Mini-Mental State was 0.69; for the standardized version it was 0.90. It took less time to administer the Standardized Mini-Mental State than the Mini-Mental State. Conclusions The Standardized Mini-Mental State had better reliability than the Mini-Mental State in this study group. Although the improved reliability of the Standardized Mini-Mental State was achieved by reducing measurement noise, this advantage would likely occur in a broad spectrum of patients.
TL;DR: The vitamin K-antagonist drugs were reviewed in the Journal in the early 1970s and their safety has been improved for a number of indications without compromising efficacy, through the use of a lower degree of anticoagulation than formerly in North America.
Abstract: The vitamin K-antagonist drugs were reviewed in the Journal in the early 1970s.1 , 2 Since then, there has been considerable progress in research at both a basic and an applied level. The mode of action of coumarins has been clarified; their role in the management of thromboembolic disorders has been more clearly defined; a system has been developed to standardize the measurement of their anticoagulant effect3; and their safety has been improved for a number of indications without compromising efficacy, through the use of a lower degree of anticoagulation than formerly in North America.4 Warfarin (a 4-hydroxycoumarin compound) is the . . .
TL;DR: This work presents one method based on stable isotope analysis in human tissues and discusses its contributions, and discusses several potential sources of variation including sex, age, nutritional status, among others.
Abstract: Extracting nutrients is of upmost importance to the sur- vival of any individual or species. One of the distinguishing characteristics of the order Primates is the vast range of nutritional adaptations it exhibits. Within our own species all manner of adaptations are practiced and it has been a major focus of research to determine when and where these various patterns originated. We present one method based on stable isotope analysis in human tissues and discuss its contributions. The ratios of l3C/''C and 15N/14N vary among various pools (i.e., the atmosphere, the oceans, plant communities, trophic levels). These differences are transferred to humans via the foods they eat. The major differences in carbon occur between two photosynthetic pathways (C3 and C4), which in the New World permits tracing the introduction of maize (a C4 plant) and in Asia permits tracing the introduction of millet (also a C4 plant). The marine and terrestrial systems have distinctive isotope ratios of both carbon and nitrogen. Thus, the dependence on marine resources has been traced throughout several areas of the New and Old Worlds. We discuss several potential sources of variation including sex, age, nutritional status, among others. We conclude with some suggestions for future research.
TL;DR: It is suggested that the FPR in normal subjects may be lower than previously believed and patients with Cushing's syndrome demonstrated unequivocal elevation of FPR and cortisol concentration correlated during each sample period in normal volunteers, indicating that cortisol secretion, rather than metabolism, is mainly responsible for changes in plasma cortisol.
Abstract: Growth retardation as well as the development of Cushingoid features in adrenally insufficient patients treated with the currently accepted replacement dose of cortisol (33-41 mumol/day.m2; 12-15 mg/m2.day) prompted us to reevaluate the cortisol production rate (FPR) in normal subjects and patients with Cushing's syndrome, using a recently developed thermospray liquid chromatography-mass spectrometry method. The stable isotope [9,12,12-2H3]cortisol was infused continuously for 31 h at about 5% of the anticipated FPR. Blood samples were obtained at 20-min intervals for 24 h, spun, and pooled in 4-h groups. Tracer dilution in plasma was determined by liquid chromatography/mass spectrometry. The method was validated with controlled infusions in 6 patients with adrenal insufficiency. Results from 12 normal volunteers revealed a FPR of 27.3 +/- 7.5 mumol/day (9.9 +/- 2.7 mg/day) or 15.7 mumol/day.m2; 5.7 mg/m2. day). A previously unreported circadian variation in FPR was observed. Patients with Cushing's syndrome demonstrated unequivocal elevation of FPR and cortisol concentration correlated during each sample period in normal volunteers, indicating that cortisol secretion, rather than metabolism, is mainly responsible for changes in plasma cortisol. Our data suggest that the FPR in normal subjects may be lower than previously believed.
TL;DR: Although approximately two thirds of the ELBW group were performing in the normal range on intellectual measures, comparison with the control group suggests that, as a group, ELBW children were significantly disadvantaged on every measure tested.
TL;DR: Elevated catecholamine levels are implicated in many of these responses and serve to protect metabolic processes against acid-base disturbances, but do not appear to contribute to EPOC directly.
Abstract: In fish, exhaustive exercise stress differs from steady-state aerobic exercise in causing (1) a depletion of glycogen, creatine phosphate (CP) and ATP reserves and an accumulation of lactate and metabolic acid (H+m) in white muscle; (2) blood respiratory and metabolic acidoses {PCO2 and H+m elevations, respectively); (3) marked ionic and fluid volume disturbances; and (4) a surge in plasma catecholamines. During recovery, the smaller fast component (20%) of excess postexercise oxygen consumption (EPOC) is explained by CP and ATP resynthesis and aerobic demands, but the larger slow component (80%) is considerably greater than the cost of lactate clearance and glycogen resynthesis. Ionic and H2O shifts may contribute significantly to EPOC; net fluxes are greatest between extracellular (ECF) and intracellular fluid (ICF) compartments, with smaller disturbances at the kidney (increased filtration, reabsorption and excretion) and gills (passive ion losses and H2O uptake). Modulation of branchial Na+ and Cl− exchange is important in the temporary storage of H+m in the environment during recovery. Movements of lactate and H+ from ICF to ECF are dissociated processes; the major portions of both are retained in the white muscle and are probably cleared by oxidation and/or glycogen resynthesis in situ. Elevated catecholamine levels are implicated in many of these responses and serve to protect metabolic processes against acid-base disturbances, but do not appear to contribute to EPOC directly. Catecholamines also cause an elevation in blood Pco2 by a mechanism linked to the β-adrenergic activation of red blood cell Na+/H+ exchange that protects O2 transport. The compound blood addosis stimulates ventilation to meet the demands of EPOC.
TL;DR: The backpropagation algorithm that provides a popular method for the design of a multilayer neural network to include complex coefficients and complex signals so that it can be applied to general radar signal processing and communications problems is generalized.
Abstract: The backpropagation (BP) algorithm that provides a popular method for the design of a multilayer neural network to include complex coefficients and complex signals so that it can be applied to general radar signal processing and communications problems. It is shown that the network can classify complex signals. The generalization of the BP to deal with complex signals should make it possible to expand the line of applications of this powerful nonlinear signal processing algorithm. >
TL;DR: The data provided a detailed description of perceptions regarding food cravings among college-age adults, but also underscored some of the limitations of self-report measures of food craving.
TL;DR: This work cued attention to a moving object and found subsequent inhibition at the locus the object later occupied, implying that previously examined objects are suppressed.
Abstract: Our response to visual events can be delayed at positions we have recently examined attentively Such inhibition could organize visual search through static scenes by suppressing those loci already searched, but this mechanism would fail in moving scenes as objects' locations then change during search We cued attention to a moving object and found subsequent inhibition at the locus the object later occupied This implies that previously examined objects are suppressed Such object-centred inhibition would be highly adaptive, but would require a sophisticated neural implementation for a mechanism held to be sub-cortical
TL;DR: The review describes the decision points in the production process for consensus recommendations as a start on the development of a set of recognized standards, and offers a critical appraisal of the various methodological choices available at each decision point.
Abstract: When existing evaluations find little or no evidence of consensus recommendations leading to action, one can justifiably ask why so much of this review was dedicated to analyzing alternative ways of producing such "words without action." There are, however, at least two reasons why consensus recommendations should be produced with care and attention to validity. First, recommendations do sometimes have an impact on behavior as a consequence of mere dissemination activity--the Dutch program, for instance, was more successful than most. This success may occur when the target audience is already particularly receptive to change and the message is timely and delivered by a credible source in a clinically relevant way. Thus, although "such a conjunction of favorable conditions is probably the exception rather than the rule for consensus topics" (46, 240) it does happen. Second, the output from consensus processes is increasingly a potential input to other processes. Consensus recommendations can be used as the criteria for evaluation and appraisal aimed at changing practice behavior, making administrative decisions on resource allocation, or defining research protocols. For instance, quality assurance activities, such as peer assessment, practitioner certification, or utilization review, are actively seeking criteria with which to make judgments and elicit changes in practice to improve the quality of care. Funding agencies are looking for information to help make reimbursement, capital expenditure, or fee-for-service decisions on cessation of insurance for particular procedures or approaches. These uses of the consensus criteria are potentially major and controversial. Therefore, even if dissemination rarely leads to action, consensus processes should still be done carefully and with valid techniques. The use of their recommendations embedded within other activities may well lead to (forced) changes in behavior. On ethical grounds alone, we should be as sure as possible that the behavior changes being implied and encouraged are indeed advisable. For these reasons, the review describes the decision points in the production process for consensus recommendations as a start on the development of a set of recognized standards. The review offers a critical appraisal of the various methodological choices available at each decision point. The seven decision points are selecting a topic, picking the consensus group, providing background preparation, identifying information inputs, choosing a group judgment process, defining the criteria for recommendations, and choosing a report preparation procedure and format. At least two important points emerged from this review. First, the research is often not well enough developed to give clear indications for many of the choices on what is the "best" alternative.(ABSTRACT TRUNCATED AT 400 WORDS)
TL;DR: In patients with evidence of depression or anxiety, or both, exercise conditioning and behavioral counseling after AMI was associated with an accelerated recovery in some outcome measures at 8 weeks, but by 12 months similar improvements were seen in both diseasespecific and generic health-related quality of life and in other outcome measures when compared with conventional care in this community.
Abstract: This investigation was designed to determine the impact of a brief period of cardiac rehabilitation, initiated within 6 weeks of acute myocardial infarction (AMI), on both disease-specific and generic health-related quality of life, exercise tolerance and return to work after AMI. With a stratified, parallel group design, 201 low-risk patients with evidence of depression or anxiety, or both, after AMI, were randomized to either an 8-week program of exercise conditioning and behavioral counseling or to conventional care. Although the differences were small, significantly greater improvement was seen in rehabilitation group patients at 8 weeks in the emotions dimension of a new disease-specific, health-related Quality of Life Questionnaire, in their state of anxiety and in exercise tolerance. All measures of health-related quality of life in both groups improved significantly over the 12-month follow-up period. However, the 95% confidence intervals around differences between groups at the 12-month follow-up effectively excluded sustained, clinically important benefits of rehabilitation in disease-specific (limitations, -2.70, 1.40; emotions, -4.86, 1.10, where negative values favor conventional care and positive values favor rehabilitation) and generic health-related quality of life (time trade-off, -0.062, 0.052; quality of well-being, -0.042, 0.035) or in exercise tolerance (-38.5, 52.1 kpm/min); also, return to work was similar in the 2 groups (relative risk, 0.93; confidence interval, 0.71, 1.64).(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: Studies of ancient human populations from North and Central America are used to show that variation in diet within a single time plane for a given “culture” is very limited except possibly where status differences occur.
TL;DR: The main purpose of the present paper is to present human timing data from experiments designed specifically to evaluate Scalar Timing, using a human analog of the animal bisection discrimination procedure.
TL;DR: The use of a nomogram for the adjustment of heparin dosage resulted in achieving a therapeutic APTT at 24 and 48 hours in a large proportion of patients and reduced periods of inadequate anticoagulation and overanticoagulations during heparIn therapy.
Abstract: A nomogram for the adjustment of heparin dosage was developed to standardize heparin therapy and to reduce delays in achieving and maintaining a therapeutic activated partial thromboplastin time (APTT) result. Fifty consecutive patients with acute venous thromboembolism had their continuous intravenous heparin therapy adjusted according to this heparin nomogram. The effect of the nomogram on heparin therapy in these patients was compared with data from 53 historical control patients. The proportion of patients in the nomogram group who reached a therapeutic APTT at 24 hours after the start of heparin therapy was 66%, which increased to 81% at 48 hours. In contrast, 37% and 58% of the control patients reached a therapeutic APTT at 24 and 48 hours, respectively. The percentage of therapeutic APTT results of the total number of APTT determinations was greater in the nomogram patients than controls. The use of this heparin nomogram resulted in (1) achieving a therapeutic APTT at 24 and 48 hours in a large proportion of patients and (2) reduced periods of inadequate anticoagulation and overanticoagulation during heparin therapy. (Arch Intern Med. 1991;151:333-337)
TL;DR: When the results of these studies are compared and aggregated where appropriate, they provide strong evidence of a causal relationship between repetitive, forceful work and the development of musculoskeletal disorders of the tendons and tendon sheaths in the hands and wrists and nerve entrapment of the median nerve at the carpal tunnel.
Abstract: In the past 10 years there has been growing awareness among occupational health professionals worldwide of the large burden of illness associated with musculoskeletal disorders of the neck and upper limbs. It has been suggested that these disorders are associated with highly repetitive work and are due, at least in part, to ergonomic factors. This review examines the epidemiologic evidence of the relationship between workplace ergonomic factors such as repetition, force, static muscle loading, and extreme joint position and the development of muscle, tendon, and nerve entrapment disorders of the neck and upper limbs of exposed workers. An extensive search for relevant studies was undertaken. Of 54 potentially relevant studies identified, three met the a priori inclusion criteria. The validity of these studies was assessed, and one study was found to have major flaws. Criteria to demonstrate causality were also applied and were met in the most rigorously conducted study. When the results of these studies are compared and aggregated where appropriate, they provide strong evidence of a causal relationship between repetitive, forceful work and the development of musculoskeletal disorders of the tendons and tendon sheaths in the hands and wrists and nerve entrapment of the median nerve at the carpal tunnel. The comparison of exposed to controls for hand/wrist tendinitis gives an unadjusted common odds ratio of 9.1 (95% CI 4.9-16.2). The adjusted odds ratio for carpal tunnel syndrome is 15.5 (95% CI 1.7-141.5) based on the most rigorous study.
TL;DR: Low molecular weightHeparin is significantly less hemorrhagic than standard unfractionated heparin; the difference in the rate of deep vein thrombosis, although not statistically significant (P greater than 0.2), favors the use of LMWheparin.
Abstract: Objective To determine the relative efficacy and safety of low molecular weight (LMW) heparin (Enoxaparin) compared with standard calcium heparin for the prevention of postoperative deep vein thrombosis in patients undergoing elective hip surgery. Design A double-blind, randomized, controlled trial. Patients Six hundred sixty-five consecutive patients undergoing hip replacement at five participating hospitals. Interventions Patients received either fixed-dose LMW heparin, 30 mg subcutaneously twice daily, or fixed-dose standard calcium heparin, 7500 units subcutaneously twice daily; both regimens were started 12 to 24 hours after surgery and continued for 14 days or until discharge if sooner. Measurements All patients had postoperative I-125-fibrinogen leg scanning and impedance plethysmography. If results of one or both tests were positive, then venography was done. Otherwise, venography was done between day 10 and day 14, or sooner if the patient was ready for discharge. Results Evaluable venograms were obtained in 258 of the 333 patients randomly assigned to receive LMW heparin and in 263 of the 332 patients assigned to receive calcium heparin. For patients with evaluable venograms, thrombosis was detected in 50 patients (19.4%) who received LMW heparin compared with 61 patients (23.2%) who received standard heparin (difference, -3.8%; 95% CI, -11.1% to 3.6%) (P greater than 0.2). Proximal deep vein thrombosis was detected in 5.4% of the patients receiving LMW heparin and in 6.5% of the patients receiving standard heparin (difference, -1.1%; CI, - 5.2% to 3.3%) (P greater than 0.2). For the entire group of 665 patients, venous thrombosis occurred in 17.1% given LMW heparin and in 19.0% given standard heparin. Hemorrhagic complications occurred in 31 patients (9.3%) given standard heparin and in 17 patients (5.1%) given LMW heparin (difference, 4.2%; CI, 0.3% to 8.2%) (P = 0.035). The relative risk reduction was 45%. The rate of major bleeding in the standard heparin group was 5.7% compared with 3.3% in the LMW heparin group (difference, 2.4%; CI, -1.0% to 5.4%) (P = 0.13). The relative risk reduction was 42%. Conclusion Low molecular weight heparin is significantly less hemorrhagic than standard unfractionated heparin; the difference in the rate of deep vein thrombosis, although not statistically significant (P greater than 0.2), favors the use of LMW heparin.
TL;DR: Measurements of the phase and modulation of amplitudemodulated light diffusely reflected by turbid media can be used to deduce absorption and scattering coefficients.
Abstract: Measurements of the phase and modulation of amplitude-modulated light diffusely reflected by turbid media can be used to deduce absorption and scattering coefficients.
TL;DR: In this article, the authors compared the local and regional history of fires in the boreal forest with the microscopic charcoal content, macroscopic charcoal, elemental carbon content, fossil pollen content, sedimentology, and geochemistry of annually laminated sediments from a small lake.
TL;DR: A consistent shift can be noticed in which subjective measures are being replaced by objective measurement methods, and the issue of the presumed superiority of objective measures is addressed in two successive papers.
Abstract: Objectivity has been one of the hallmarks in the assessment of clinical competence in recent decades. A consistent shift can be noticed in which subjective measures are being replaced by objective measurement methods. In the transition from subjective to objective methods trade-offs are involved, both in the effort expended and in the range of behaviours assessed. The issue of the presumed superiority of objective measures is addressed in two successive papers. In this paper a distinction is made between objectivity as a goal of measurement, marked by freedom of subjective influences in general, and objectivity as a set of strategies designed to reduce measurement error. The latter has been termed objectification. The central claim of this paper is that these two approaches to assessment do not necessarily coincide. By reviewing a number of studies comparing subjective and objectified measurement methods, the claim of the supremacy of the latter with respect to reliability is discussed. The results of these studies indicate that objectified methods do not inherently provide more reliable scores. Objectified methods may even provide unwanted outcomes, such as negative effects on study behaviour and triviality of the content being measured. The latter issues, related to validity, efficiency and acceptability, are discussed in a second paper.