SEARCH · PubMed Health

Results for “Comparison”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources

PubMed1999

Social comparison, self-esteem and depression in people with intellectual disability.

The present study explores the relationship between social comparison processes, self-esteem and depression in people with intellectual disability. Forty-three people with mild and moderate intellectual disability completed adapted measures of self-esteem and social comparison. The social comparison scale offers subscale scores on achievement, social attractiveness and group belonging dimensions. The self-esteem scale offers subscale scores for positive and negative self-esteem. A significant positive correlation was found between positive self-esteem and social comparison on the achievement dimension. Depression was significantly negatively correlated with social comparison on the social attractiveness and group belonging dimensions, and with positive self-esteem. Regression analysis showed that depression was significantly and independently predicted only by social comparison on the social attractiveness dimension. The present authors conclude that social comparison is associated with self-esteem and depression in people with intellectual disability in the same way as it is for people without intellectual disability. Further exploration of social comparison process in people with intellectual disability may inform cognitive behavioural interventions for this group of people.

Adult↗

PubMed1991

Paired comparison judgments for hearing aid selection in children.

Three experiments were conducted to investigate the feasibility of using a paired comparison technique to select hearing aids for children. The first two experiments determined the age at which normal-hearing children and hearing-impaired children with mild to moderately severe sensorineural hearing loss could be expected to meet criteria on a paired comparison task involving judgments of auditory clarity. Of 25 normal-hearing children between the ages of 4.0 and 6.4 yr, five out of five children between 6.0 and 6.4 yr of age passed the auditory paired comparison task. Of 10 hearing-impaired children between the ages of 5.5 and 7.4 yr, five out of five children between 6.5 and 7.4 yr of age passed the auditory paired comparison task. In Experiment 3, eight hearing-impaired children between the ages of 5.7 and 7.8 yr judged the clarity of seven hearing aids in two paired comparison, round robin tournaments. The results showed that correlations between the two tournaments were moderate to strong for six children and weak for two children. Of the six children with stronger correlations between tournaments, correlations between paired comparison judgments and phoneme identification scores were moderate to strong for four children and weak for two children. When compared with a hearing aid that approximated a standard prescription, the hearing aid selected by the paired comparison technique neither degraded nor enhanced speech intelligibility. Results from this study indicate that a paired comparison technique is feasible for use with hearing-impaired children 6.5 yr of age, and occasionally younger, who exhibit mild to moderately severe sensorineural hearing loss and are capable of performing the task reliably.

Age Factors↗

PubMed1997

Subjective judgments of speech clarity measured by paired comparisons and category rating.

OBJECTIVE: The purpose of this study was to compare listeners' subjective judgments of speech clarity via paired comparisons and category rating using stimulus conditions that varied in the relative spacing between stimulus items, producing either a wide or narrow range of performance. DESIGN: Subjective judgments of speech clarity were measured via paired comparisons and category rating in 12 normal-hearing (Experiment 1) and eight hearing-impaired adults (Experiment 2). Sentences processed by six band-pass filters that increased monotonically in Articulation Index (AI) estimates constituted the stimuli to be judged. Using subsets of three filters from the group of six, subjective judgments were additionally obtained for stimulus conditions in which the performance ranges were wide (large differences in AI) and narrow (small differences in AI). RESULTS: Speech clarity judgments obtained by paired comparisons and category rating were highly related to the AI estimates both for normal-hearing and hearing-impaired subjects. When the performance range was wide, both methods provided similar judgments for the normal-hearing subjects. For the hearing-impaired subjects, paired comparisons were more sensitive than category rating. When the performance range was narrow, paired comparisons were more sensitive than category rating in differentiating between filters for both groups of subjects. This difference was less obvious for the normal-hearing subjects when paired comparison data were converted to a scale comparable to the category ratings. Large between-subject variability was evident for the hearing-impaired subjects on the psychophysical scaling procedures, most notably for category rating. CONCLUSIONS: When judging the clarity among stimulus items where performance varied over a wide range, both category rating and paired comparisons provided comparable judgments for normal-hearing listeners. For conditions in which perceptual differences between stimulus items were restricted either by the choice of conditions or by the effects of sensorineural hearing loss, the method of paired comparisons was the more sensitive procedure.

Adult↗

PubMed2005

Orphan comparisons and indirect meta-analysis: a case study on antidepressant efficacy in dysthymia comparing tricyclic antidepressants, selective serotonin reuptake inhibitors, and monoamine oxidase inhibitors by using general linear models.

Direct comparisons of the efficacy of competing interventions are not always available in the literature. This situation leads to the presence of clinically relevant "orphan comparisons" of therapeutic interventions which have never been compared head-to-head. To overcome this limitation, simple methods for indirect meta-analysis have been suggested. Nevertheless, their results are prone to bias when more than 1 indirect comparison is tested because of the likely duplication of data for some comparisons. In contrast, general linear models can be used to extend simple indirect meta-analysis beyond 1 indirect comparison by fitting to incomplete data using maximum likelihood within the framework of multitreatment comparisons. This study presents a tutorial application of general linear models to the comparative efficacy of several antidepressants in dysthymia (tricyclic antidepressants, selective serotonin reuptake inhibitors, and monoamine oxidase inhibitors. Working with previously published data comparing the efficacy of antidepressants with placebo, it is shown that tricyclic antidepressants and selective serotonin reuptake inhibitors present similar efficacy (odds ratio = 1.19, P = 0.37; relative risk = 1.10, P = 0.24; risk difference = 0.03, P = 0.53), whereas monoamine oxidase inhibitors outperform both tricyclic antidepressants and selective serotonin reuptake inhibitors, at least for some effect scales (odds ratio = 1.57, P = 0.05; relative risk = 1.25, P = 0.05; risk difference = 0.09, P = 0.08). This finding, which is an instance of a relevant orphan comparison and could not be obtained otherwise, could motivate the conduct of clinical trials or focused systematic reviews to support or refute its importance through appropriate head-to-head comparisons.

Antidepressive Agents, Tricyclic↗

PubMedDate not supplied

Sibling comparison of differential parental treatment in adolescence: gender, self-esteem, and emotionality as mediators of the parenting-adjustment association.

This study employs findings from social comparison research to investigate adolescents' comparisons with siblings with regard to parental treatment. The sibling comparison hypothesis was tested on a sample of 516 two-child families by examining whether gender, self-esteem, and emotionality-which have been found in previous research to moderate social comparison-also moderate sibling comparison as reflected by siblings' own evaluations of differential parental treatment. Results supported a moderating effect for self-esteem and emotionality but not gender. The sibling comparison process was further examined by using a structural equation model in which parenting toward each child was associated with the adjustment of that child and of the child's sibling. Evidence of the "sibling barricade" effect-that is, parenting toward one child being linked with opposite results on the child's sibling as on the target child-was found in a limited number of cases and interpreted as reflecting a sibling comparison process. For older siblings, emotionality and self-esteem moderated the sibling barricade effect but in the opposite direction as predicted. Results are discussed in terms of older siblings' increased sensitivity to parenting as well as the report of differential parenting reflecting the child's level of comfort and benign understanding of differential parenting, which buffers the child against environmental vicissitudes evoking sibling comparison processes.

Adolescent↗

PubMed2003

Are some risk comparisons more effective under conflict?: a replication and extension of Roth et al.

Despite many claims for and against the use of risk comparisons in risk communication, few empirical studies have explored their effect. Only one study, published by Roth et al. in this journal in 1990, has tested the 1988 predictions by Covello et al. as to the public's relative preferences for 14 kinds of risk comparisons as they might be used by a factory manager to explain risks of his ethylene oxide plant. That study found no correlations between the Covello predictions and seven different measures of "acceptability" of Covello's examples of each type of comparison. However, two critics of the Roth study, as well as its own authors, suggested that a scenario involving local risks, a conflict-ridden situation, and a plant manager unknown to the townspeople might better evoke Covello-like preferences than the distant, calm, friends-involving scenario used by Roth. The research reported here replicated the Roth study using the same scenario, risk comparison examples, and evaluation measures, and added a second scenario intended to replicate the conditions suggested by critics. Over 200 New Jersey residents answered the study questionnaire. The replication scenario reproduced Roth's results, and the conflict scenario also evoked no rankings correlated with Covello's predictions. Furthermore, neither agreement nor disagreement with five statements representing "conflict"--respondents' reports that the industrial-plant scenario made them angry, they lived near industry, they were concerned about industrial risks, people in their home town were angry about industrial pollution, and they worried "frequently" about long-term effects of pollution--correlated with Covello's predictions. Over half of all ratings ascribed to the comparisons in aggregate were positive, and most detailed comments offered by respondents also were positive, despite many criticisms and suggestions for their improvement. The wide variability in individuals' rankings also undermines the notion of any single ranking of preferred comparisons. These findings have implications for use of risk comparisons, but also reveal the inaccuracy of the field's assumptions about public reaction to industrial risk information, including risk comparison.

Adolescent↗

PubMed2004

Response-selection-related parietal activation during number comparison.

Neuroimaging studies of number comparison have consistently found activation in the intraparietal sulcus (IPS). Recently, it has been suggested that activations in the IPS vary with the distance between the numbers being compared. In number comparison, the smaller the distance between a number and the reference the longer the reaction time (RT ). Activations in the right or left IPS, however, have also been related to attentional and intentional selection. It is possible, therefore, that activity in this region is a reflection of the more basic stimulus and response-selection processes associated with changes in RT. This fMRI experiment investigated the effect of numerical distance independently from RT. In addition, activations during number comparison of single-digit and double-digit stimuli were compared. During number comparison blocks, subjects had to indicate whether digits were greater or smaller than a reference (5 or 65). In control blocks, they were asked to perform a perceptual task (vertical line present/absent) on either numerical or nonnumerical stimuli. Number comparison versus rest yielded a large bilateral parietal-posterior frontal network. However, no areas showed more activation during number comparison than during the control tasks. Furthermore, no areas were more active during comparison of numbers separated by a small distance than comparisons of those separated by a large distance or vice versa. A left-lateralized parietal-posterior frontal network varied significantly with RT. Our findings suggest that magnitude and numerical-distance-related IPS activations might be difficult to separate from fundamental stimulus and response-selection processes associated with RT changes. As is the case with other parameters, such as space, magnitude may be represented in the context of response selection in the parietal cortex. In this respect, the representation of magnitude in the human IPS may be similar to the representation of magnitude in other nonhuman primates.

Adult↗

PubMed1997

[Statistical analysis of pharmacological data: problem of multiple comparison].

Problems of multiple comparison were discussed without assuming technical knowledge of statistics. For the first question concerning why to use multiple comparison procedures, theoretical bases of statistical inference and multiple comparison (including type I error rate and familywise error rate) were briefly outlined. For the second question concerning how to properly use multiple comparison procedures, multiple comparison procedures were introduced, and their characteristics were compared. Families of comparisons are different among Dunnett's, Tukey's and Scheffe's tests. Assumptions of dose-response relationship are different among Dunnett's, Williams' tests and linear regression analysis. Duncan's test does not control familywise error rate at a fixed level. For the last question concerning what is remarked for multiple comparison, approaches to several problems such as abnormality and heteroscedasticity were provided. Philosophy and strategy to multiple comparison problems were discussed.

Data Interpretation, Statistical↗

PubMed2004

The impact of personal and social comparison information about health risk.

OBJECTIVES: To examine the emotional and cognitive impact of personal and social comparison information about health risk. METHODS: A total of 970 adults responded to vignettes describing risk presentation scenarios that varied in terms of having (a) a 'real world' analogue (cardiac event) versus no such analogue (a fictitious pancreatic disease) condition, (b) high versus low levels of personal risk, and (c) no comparison group information given, comparison group risk higher or lower than own risk. RESULTS: For both the cardiac and pancreatic disease vignettes, respondents' emotional responses and estimates of their own risk were influenced by both personal and social comparison risk information. The cardiac event vignettes produced larger effects than the pancreatic disease vignettes. Unfavourable social comparison information had no discernible impact, relative to not providing any social comparison information. Favourable social comparison information resulted in greater reassurance, less worry, and perceptions of lower susceptibility. Lower personal risk generally produced similar effects, relative to higher personal risk. CONCLUSIONS: In contrast to previous theory and research in this area, we found that both personal and (favourable) social comparison risk information have emotional and cognitive consequences. We hypothesize that the perceived clarity of the information may account for the different patterns of findings in the literature.

Adult↗

PubMed1989

Principles of biological comparison.

The problems of comparative analyses in biology have been discussed, showing that a single comparative method does not exist. Several principles of comparison are elucidated, which include that comparisons do not have to possess a phylogenetic basis, can be horizontal or vertical, and can be genetic or nongenetic. Biological comparisons can be grouped roughly into historical and nonhistorical ones. Historical comparisons depend on the details of evolutionary theory, and include: (a) comparisons on which phylogenies and classifications are based; and (b) comparative studies using these phylogenies and classifications. Nonhistorical comparisons require pertinent nomological relationships between two or more variables, and include: (a) comparisons between variables used to elucidate these law-like relationships; and (b) comparisons in which unknown properties of one variable are deduced from the known properties of other variables - extrapolations made in biology.

Anatomy, Comparative↗

PubMed1995

Meeting goals and confronting conflict: children's changing perceptions of social comparison.

It was proposed that previously observed grade-related changes in children's social comparison behavior could be explained by the changing goals and meanings children assign to this behavior. Specifically, it was suggested that, as children progress through the school system, they become increasingly aware of the negative and positive aspects of social comparison and adjust their behavior in response to this awareness, as well as to increasingly salient self-evaluation goals. To examine these propositions, 106 elementary school children were observed in their classrooms and interviewed once a year for 3 years. Consistent with previous research, overt forms of social comparison were most frequent among younger children, whereas subtle forms of social comparison were most frequent among older children. Furthermore, with increasing grade children were likely to view overt forms of social comparison negatively and subtle forms as useful in meeting self-evaluation goals. Additional analyses revealed little association between perceptions of social comparison and actual social comparison behavior, except that perceiving subtle social comparison as useful for self-evaluative goals predicted engagement in such behavior 2 years later.

Child↗

PubMed2005

Comparisons and perceived deprivation in ethnic minority settings.

Two studies investigated comparison choices among ethnic minorities and majorities. The perceived status of the self vis-á-vis different comparison targets also was assessed. Antecedents and consequences of comparisons and relative deprivation were examined. Predictions were derived from social comparison, stigma, social identity, and relative deprivation research. Two surveys were conducted, one in London with mainly Asian participants (N = 235) and one in Germany with Turkish and Aussiedler participants (N = 166) and German majority members (N = 351). Participants preferred intragroup and temporal comparisons (with other ingroup members and with the self in the past) to various types of cross-group comparisons (with outgroup members). Perceived similarity and contact with a target positively predicted interest in comparing with this target, and perceived higher status of the target was a negative predictor. Some evidence was found that feelings of deprivation depend on comparison choices. Deprivation negatively predicted self-esteem and life satisfaction. Deprivation and group identification were negatively correlated.

Adolescent↗

PubMed2002

Comparison of sequence and structure alignments for protein domains.

Profile search methods based on protein domain alignments have proven to be useful tools in comparative sequence analysis. Domain alignments used by currently available search methods have been computed by sequence comparison. With the growth of the protein structure database, however, alignments of many domain pairs have also been computed by structure comparison. Here, we examine the extent to which information from these two sources agrees. We measure agreement with respect to identification of homologous regions in each protein, that is, with respect to the location of domain boundaries. We also measure agreement with respect to identification of homologous residue sites by comparing alignments and assessing the accuracy of the molecular models they predict. We find that domain alignments in publicly available collections based on sequence and structure comparison are largely consistent. However, the homologous regions identified by sequence comparison are often shorter than those identified by 3D structure comparison. In addition, when overall sequence similarity is low alignments from sequence comparison produce less accurate molecular models, suggesting that they less accurately identify homologous sites. These observations suggest that structure comparison results might be used to improve the overall accuracy of domain alignment collections and the performance of profile search methods based on them.

Animals↗

PubMed2002

Standardization using the harmonically weighted ratios: internal and external comparisons.

Standardization of rates is a basic tool for epidemiologists. The most frequently used methods are the 'direct standardization' (with summary index of comparative mortality figure, CMF) and the 'indirect standardization' (with summary index of standardized mortality ratio, SMR). The CMF facilitates a valid comparison between populations or across time periods, yet, it suffers from the problem of instability. By contrast, the SMR is stable and can be used for external comparison. However, it cannot guarantee a valid internal comparison. In this paper, the author proposes a new standardized measure, the 'harmonically weighted ratio' (HWR). The HWR can be used for external as well as internal comparisons--with the assumption of rate-ratio homogeneity, or with heterogeneity but dominance of one population over another. Simulation shows that its performance in terms of pairwise comparisons is the best among the three methods or compares favourably to that of the SMR. The author also examines the behaviours of the HWR when used for hypothesis testing (the 'HWR test'). The HWR can be considered for standardization when the purpose of the standardization is solely for comparison and when the universe of the comparisons can be clearly defined.

Adolescent↗

PubMed2001

A comparison of classification algorithms to automatically identify chest X-ray reports that support pneumonia.

We compared the performance of expert-crafted rules, a Bayesian network, and a decision tree at automatically identifying chest X-ray reports that support acute bacterial pneumonia. We randomly selected 292 chest X-ray reports, 75 (25%) of which were from patients with a hospital discharge diagnosis of bacterial pneumonia. The reports were encoded by our natural language processor and then manually corrected for mistakes. The encoded observations were analyzed by three expert systems to determine whether the reports supported pneumonia. The reference standard for radiologic support of pneumonia was the majority vote of three physicians. We compared (a) the performance of the expert systems against each other and (b) the performance of the expert systems against that of four physicians who were not part of the gold standard. Output from the expert systems and the physicians was transformed so that comparisons could be made with both binary and probabilistic output. Metrics of comparison for binary output were sensitivity (sens), precision (prec), and specificity (spec). The metric of comparison for probabilistic output was the area under the receiver operator characteristic (ROC) curve. We used McNemar's test to determine statistical significance for binary output and univariate z-tests for probabilistic output. Measures of performance of the expert systems for binary (probabilistic) output were as follows: Rules--sens, 0.92; prec, 0.80; spec, 0.86 (Az, 0.960); Bayesian network--sens, 0.90; prec, 0.72; spec, 0.78 (Az, 0.945); decision tree--sens, 0.86; prec, 0.85; spec, 0.91 (Az, 0.940). Comparisons of the expert systems against each other using binary output showed a significant difference between the rules and the Bayesian network and between the decision tree and the Bayesian network. Comparisons of expert systems using probabilistic output showed no significant differences. Comparisons of binary output against physicians showed differences between the Bayesian network and two physicians. Comparisons of probabilistic output against physicians showed a difference between the decision tree and one physician. The expert systems performed similarly for the probabilistic output but differed in measures of sensitivity, precision, and specificity produced by the binary output. All three expert systems performed similarly to physicians.

Acute Disease↗

PubMed2006

Statistical validation of two sample comparison methods for oligonucleotide microarray in rat ischemia model.

In gene expression analyses using a high-density oligonucleotide array in a rat ischemia model, two comparison methods, "pair-wise comparison" and "sample average comparison", were evaluated based on statistical methods. The reliability of the elements screened with a 1.2 to 10-fold threshold was also evaluated. In pair-wise comparisons, most of the elements were significantly independent of the threshold value, with the percentage of significant elements remaining above 95%, when screened at 2.5-fold or higher threshold value. Pair-wise comparison structurally provided strict screening, which resulted in genes that were not selected despite significant alterations in expression. Screening by "sample average comparison" resulted in elements with low probability of significance, which suggested the necessity for increasing the reliability by additional statistical analyses after screening. When genes with altered expression were screened using an oligonucleotide array, marked differences in the numbers and reliability were proved to exist among elements screened by each sample comparison method.

Animals↗

PubMed1989

Identification of unknown human remains by comparison of antemortem and postmortem radiographs.

The identification of unknown human remains by comparison of ante mortem and post mortem radiographs has found wide acceptance in recent years. This report documents two recent cases in Hong Kong in which unequivocal positive identifications were achieved by comparison of radiographs. In both cases, comparison of radiographs was the only available means of establishment of personal identity. The first case involved the identification of a very badly burned body of a 22-year-old male by the matching of the ante mortem and post mortem radiographic images of the cranial base (in particular the sella turcica), hard palate, paranasal air sinuses, mastoid air cells, the lambdoid suture, and the upper molar teeth as revealed on comparable lateral skull films. The second was the identification of a deliberately mutilated torso of a 28-year-old female by comparison of the radiographic images of the lumbar spine, pelvis, and head of the femur as revealed on plain abdominal films taken before and after death. While evidence of injury or surgery did not figure in either of the identifications, the presence of a mild scoliosis and the absence of the twelfth ribs aided identification in the latter case. Emphasis is placed in this account on the value of radiographic comparison as a means of identification because it draws upon the matching of intricate and highly individual patterns of external and internal bony anatomy that are stable over long periods of time. In cases where ante mortem radiographs and photographs are available, establishment of personal identity by comparison of radiographs is deemed preferable to identification by photographic superimposition because radiographic comparison permits the matching of a potentially larger number of unique anatomical features and is less time consuming and technically exacting.

Adult↗

PubMedDate not supplied

Methylmercury developmental neurotoxicity: a comparison of effects in humans and animals.

A qualitative and quantitative comparison of the neuropathological and neurobehavioral effects of early methylmercury (MeHg) exposure is presented. The focus of the qualitative comparison is the examination of how specific end-points (and categories of behavioral functions) compare across species. The focus of the quantitative comparison is the investigation of the relationship between MeHg exposure, target-organ dose and effects in humans and animals. The results of the comparisons are discussed in the context of the adequacy of the proposed EPA neurotoxicity battery to characterize the risk of MeHg to humans. The comparisons reveal several qualitative and quantitative similarities in the neuropathological effects of MeHg on humans and animals at high levels of exposure. Reports of neuropathological effects at lower levels are available for animals only, precluding any comparison. At high levels of exposure, specific neurobehavioral end-points affected across species are also similar. Effects at lower levels of exposure are similar if categories of neurobehavioral functioning are compared. Changes in the EPA test battery consistent with the results of the comparisons are discussed.

Animals↗