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 397 records · Page 22Linked to original sources

PubMed1992

A comparison of neurological assessment scores from two cohorts of low-birthweight children evaluated at age four years: Dublin and Copenhagen.

We compared the neurological condition and functions at age 4 years for two cohorts of children initially treated in the neonatal intensive care units in two countries: Denmark (10) and Ireland (2). The comparisons were made in two ways: first, the more usual comparison between frequencies of cerebral palsy, mental retardation, hydrocephalus, visual and hearing loss. A second comparison was based on the items, subscales, and total scores on a neurological battery developed from the Danish data. Comparisons were made among three different birthweight groups within each country as well as between countries using analysis of variance (ANOVA). In both cohorts, significant differences were shown between two subgroups: those with birthweights less than 2300 gms and those with birthweights over 2500 gms for all subscales except the neurological ones in the Irish cohort. In the Danish cohort, significant differences were shown on all subscales among three birthweight groups: less than 1501 gms; 1501-2300 gms; and over 2500 gms. Significant differences were shown between countries for easy drawing, neurology "b", and fine motor testing.

Blindness↗

PubMed1980

Lipids and lipoproteins in Venezuelan and American schoolchildren: within and cross-cultural comparisons.

This study was designed to focus upon within-culture differences in plasma lipids and lipoproteins in Venezuelan schoolchildren having different socioeconomic and nutritional backgrounds and also to provide cross-cultural comparisons of lipids, lipoproteins, and anthropometric measurements between Venezuelan and American schoolchildren. The study was carried out in 1298 schoolchildren, ages 7 to 12 years, 428 in private and 870 in public schools in Merida, Venezuela, with comparison to 472 public schoolchildren in the (Cincinnati, OH) Princeton School District. Within Venezuelan schools, private shcoolchildren were heavier, taller, had marginally higher Quetelet indices, and had considerably higher fasting plasma cholesterol, plasma high-density lipoprotein (C-HDL), and plasma low-density lipoprotein (C-LDL) levels. These lipid-lipoprotein differences were highly significant after adjusting (by covariance analysis) for Quetelet index, sex, and age. Children from private Venezuelan schools ingested more total calories, more protein, more fat, and more carbohydrate. When the diet compositions were calculated as percentage of total calories, the private schoolchildren ingested nearly twice as many calories as fat and a somewhat lower proportion of calories as carbohydrate, with a comparable proportion as protein, when compared to the public Venezuelan schoolchildren. Male-female comparisons within Venezuelan schools revealed patterns of sex-related lipoprotein differences which were qualitatively similar to those in Princeton schoolchildren. Thus, 7- to 12-year-old females had higher total plasma cholesterol and triglyceride, lower C-HDL, and higher C-LDL. Within sex, cross-cultural comparisons of lipids, lipoproteins, and Quetelet indices revealed two major differences. Venezuelan children had significantly higher fasting plasma triglyceride and lower C-HDL levels, differences not attributable to systematic differences in measures of ponderosity, because Quetelet indices in Venezuelan and Cincinnati schoolchildren did not differ appreciably. In regard to total and low-density lipoprotein cholesterol, Venezuelan and Princeton public schoolchildren were remarkably comparable, although Venezuelan private schoolchildren had somewhat higher plasma cholesterol and C-LDL levels than did Princeton public schoolchildren. We speculate that increasing "westernization" and "urbanization" of Venezuelan society is associated with convergence of Venezuelan and American pediatric plasma lipid and lipoprotein levels. Maintenance of comparable total plasma cholesterol and C-LDL levels with lower C-HDL into adulthood in Venezuela would, in fact, suggest augmented risks for coronary heart disease for Venezuela within this lipid-lipoprotein frame of reference.

Age Factors↗

PubMed2026

Matching-adjusted indirect comparison of fruquintinib versus ramucirumab in advanced gastric or gastroesophageal junction adenocarcinoma.

Aim: Fruquintinib (Fruq), a selective VEGFR 1/2/3 inhibitor, showed a significant progression-free survival (PFS) benefit in the Phase III FRUTIGA trial for advanced gastric/gastroesophageal junction (G/GEJ) adenocarcinoma. Ramucirumab (RAM), an anti-VEGFR2 antibody, demonstrated efficacy in the RAINBOW-Asia trial. This anchored matching-adjusted indirect comparison (MAIC) evaluated Fruq plus paclitaxel versus RAM plus paclitaxel as second-line therapy for G/GEJ adenocarcinoma in the absence of head-to-head trials. Materials & methods: Data from individual patients in the FRUTIGA study (N = 703) and aggregated data from the RAINBOW-Asia study (N = 440) were analyzed. Baseline characteristics were balanced using entropy balancing. The placebo plus paclitaxel (PBO + PTX) groups served as the common comparators. The primary outcome was PFS; secondary outcomes included overall survival, objective response rate (ORR) and disease control rate (DCR). Rates of treatment-emergent adverse events (TEAEs) were also compared as an exploratory outcome using an adjusted indirect risk difference. Sensitivity analyses included restricted mean survival time and simulated treatment comparison. Results: After weighting (effective sample size = 564), baseline covariates were balanced. The anchored MAIC demonstrated that Fruq + PTX significantly improved PFS compared with RAM + PTX (HR: 0.70; 95% CI: 0.51-0.96; p = 0.0280), corresponding to a 30% reduction in progression risk, with a significant restricted mean survival time benefit of 1.18 months at 20 months (95% CI: 0.08-2.27; p = 0.024). Fruq achieved significantly higher ORR (OR: 1.76, 95% CI: 1.16-2.68; p = 0.008) and DCR (OR: 1.94, 95% CI: 1.33-2.83; p < 0.001). Overall survival was similar (0.97; 95% CI: 0.73-1.30; p = 0.8640). Subgroup analyses showed PFS benefits with Fruq in patients with ECOG PS 1, peritoneal metastases and two or fewer metastatic sites. In sensitivity analysis, the simulated treatment comparison also suggested a PFS benefit for Fruq + PTX (HR: 0.40, 95% CI: 0.32-0.50; p < 0.0001). For any-grade TEAEs, the indirect comparison showed higher adjusted relative incidences of increased bilirubin with Fruq + PTX than with RAM + PTX (RD: 12.3%; 95% CI: 2.3-22.4%, p < 0.05) and of hypokalemia (RD: 9.0%; 95% CI: 1.5-16.4%, p < 0.05). For grade ≥3 TEAEs, the adjusted relative incidence of decreased body weight was higher with Fruq + PTX than with RAM + PTX (RD: 2.9%; 95% CI: 0.6-5.2%, p < 0.05). The adjusted relative incidences of increased AST, ALT and hypocalcemia were numerically lower in the fruquintinib group than in the RAM group. Conclusion: This MAIC indicates that Fruq + PTX may be more effective than RAM + PTX in second-line advanced G/GEJ adenocarcinoma, with potentially improved PFS, ORR and DCR, and similar overall survival. Safety analyses suggested generally comparable safety profiles across the two regimens. Fruq + PTX remains a valuable treatment option, offering important comparative evidence for clinical and health technology assessment decisions. Trial Registration: Clinicaltrials.gov identifiers: NCT07144995.

Adult↗

PubMed2002

What's wrong with cross-cultural comparisons of subjective Likert scales?: The reference-group effect.

Social comparison theory maintains that people think about themselves compared with similar others. Those in one culture, then, compare themselves with different others and standards than do those in another culture, thus potentially confounding cross-cultural comparisons. A pilot study and Study 1 demonstrated the problematic nature of this reference-group effect: Whereas cultural experts agreed that East Asians are more collectivistic than North Americans, cross-cultural comparisons of trait and attitude measures failed to reveal such a pattern. Study 2 found that manipulating reference groups enhanced the expected cultural differences, and Study 3 revealed that people from different cultural backgrounds within the same country exhibited larger differences than did people from different countries. Cross-cultural comparisons using subjective Likert scales are compromised because of different reference groups. Possible solutions are discussed.

Adult↗

PubMed1988

Reliability of brightness comparison testing in predicting afferent pupillary defects.

We tested the reliability of brightness comparison testing in predicting relative afferent pupillary defects (RAPDs) in 206 patients. For unselected patients, brightness comparison testing correctly predicted the RAPD in 62% of patients. For subgroups of patients with glaucoma and optic nerve lesions, correct predictions were made in 92% and 83% of patients, respectively. Sensitivity and specificity of brightness comparison testing with a 6-V test light were 85% and 49%, respectively. In subgroups of patients who are strongly suspected of having an RAPD but in whom pupillary testing is not possible, brightness comparison testing can reliably predict presence or absence of an RAPD.

Amblyopia↗

PubMed2006

Disentangling the relation between television viewing and cognitive processes in children with attention-deficit/hyperactivity disorder and comparison children.

OBJECTIVES: To develop causal hypotheses regarding the effects of television viewing on cognitive processes in children and to examine the proposition that deleterious effects of television may be stronger among children with attention-deficit/hyperactivity disorder. DESIGN: Longitudinal study involving 2 phases occurring 18 months apart. SETTING: University research facilities in Lexington. PARTICIPANTS: Fifty-nine children with attention-deficit/hyperactivity disorder and 106 comparison children. The children's mean age was 7.18 years at phase 1 and 8.74 years at phase 2. MAIN OUTCOME MEASURES: Laboratory measures of visual attention to television, cognitive engagement to televised stories, factual recall of televised stories, and causal recall of televised stories. Parental reports of a child's weekly television viewing. RESULTS: Among comparison children, phase 1 television viewing negatively predicted phase 2 visual attention and phase 2 cognitive engagement (after accounting for phase 1 levels of the outcome variables and any relevant demographic variables). Also among comparison children, phase 1 attention negatively predicted phase 2 television viewing, even after accounting for phase 1 levels of television viewing and relevant demographic variables. These patterns were not observed among children with attention-deficit/hyperactivity disorder. CONCLUSIONS: Contrary to recent arguments, television viewing was associated with cognitive abilities in comparison children but not children with attention-deficit/hyperactivity disorder, a finding that suggests more careful examinations of the relation between television viewing and children's cognitive abilities are in order. Future studies should consider the possibility that any effects of television may be limited to certain developmental periods.

Attention↗

PubMed2000

On the relative sample size required for multiple comparisons.

Multiple comparisons are commonly made in epidemiologic and genetic research. How to appropriately adjust for multiple comparisons remains a controversial issue. This note demonstrates, however, that large increases in the number of comparisons has a limited effect on the sample size required to maintain an experimentwise alpha-level. In particular, the relative sample size required increases only linearly with the logarithm of the number of comparisons made.

Models, Statistical↗

PubMed1997

Identifying comparison groups for evaluating occupational hearing loss: a statistical assessment of 22 industrial populations.

Finding appropriate comparison groups to study occupational hearing loss has been difficult. Recently, however, the National Institute for Occupational Safety and Health sponsored the complication of potentially useful data from 22 diverse industrial companies in the U.S.A. and Canada. We conducted a statistical evaluation to determine which of the 22 populations might be suited as comparison groups in future studies of workers exposed to hazardous noise. In a Cox Proportional Hazards model that included age and sex, the relative risk of developing hearing loss in each company was estimated at two, five, and ten years of follow-up. We ranked the companies based on their relative risks, and rated them on a five-point scale from "excellent" to "poor" to indicate their suitability as comparison groups. The risk profiles developed and other variables described in this study will assist researchers in selecting appropriate comparison groups for evaluating occupational hearing loss.

Age Distribution↗

PubMed2004

Thin ideals in music television: a source of social comparison and body dissatisfaction.

OBJECTIVE: The study investigated the impact of thin idealized images of women as presented in music television, a popular form of entertainment for young people. METHODS: A sample of 84 women viewed a videotape containing either appearance music videos (which emphasized appearance and featured thin and attractive women) or non-appearance music videos. The instructional set was also manipulated to encourage or discourage social comparison. RESULTS: Viewing the appearance music videos featuring thin women led to increased social comparison and body dissatisfaction. Regression analyses showed that the effect of video condition on body dissatisfaction was mediated by the level of comparison processing. DISCUSSION: The study demonstrated that the content of television programming can have negative consequences for women's body image. In addition, it offered social comparison processing as both a theoretic mechanism and a practical target for intervention.

Adolescent↗

PubMed1995

Body size preferences and desired weight of patients who have received obesity surgery and of comparison adults.

Patients who had received obesity surgery (n = 144) and comparison adults (n = 72) selected the most attractive male and female size and the same-sex size they most wanted to look like from an array of 15 outline drawings. Subjects also reported their height, and current and desired weights (transformed into body mass index units [BMI]). There was a remarkable consensus on the sizes considered most attractive: Two male sizes were chosen by 78% of all subjects, and two female sizes by 83%. The hypothesis that adults who had obesity surgery would idealize thin sizes and, therefore, select thinner sizes and lower weights than comparison adults was not supported. Not only did patients and comparison adults select the same desired size, but women patients desired significantly larger BMIs than comparison women. There was a large range of desired BMIs associated with each desired size; the correlation between desired BMI and desired size was significant for women but not for men. It was speculated that subjects' desired size reflected cultural norms while subjects' desired BMI was a function of their current weight. Health professionals working in weight loss and/or physical fitness areas need to help clients understand weight-size relationships so that clients can have both realistic weight and realistic size goals.

Adult↗

PubMed2001

An efficient cis-element discovery method using multiple sequence comparisons based on evolutionary relationships.

The discovery of cis-element control motifs in noncoding DNA poses a difficult problem in genome analysis. Functional analysis by means of reporter constructs expressed in transgenic organisms is the most reliable method, but is by itself time-consuming and expensive. Searching noncoding DNA for known control motifs by sequence analysis is problematic, since protein binding motifs are short, in the range of 8-10 bp, and occur frequently by chance. Heretofore, the most reliable sequence analysis method has been the comparison of homologous sequence domains in related but moderately evolutionarily divergent species such as, for example, mouse and human. In such pairwise combinations, control regions are conserved because they serve a vital function and can be identified by their similar sequences. Single pairwise comparisons, however, allow the discovery of conserved sequence strings only at low resolution and without specific identity. We have investigated the possibility of using multiple sequence comparisons to correct these shortcomings. We applied this method to the Hoxc8 early enhancer region that has been previously analyzed in depth by functional methods and through its application successfully identified known protein binding cis-element motifs. Candidate protein binding sites could also be identified. This method, based on evolutionarily related sequence comparisons, should be quite useful as a prescreening step prior to functional analysis with corresponding savings in time and resources.

Animals↗

PubMed1999

Comparison Opportunity and Judgment Revision.

Prior evaluations are frequently challenged and need to be revised. We propose that an important determinant of such revisions is the degree to which the challenge provides an opportunity to compare the target against a competitor. Whenever a challenge offers an opportunity, the information contained in the challene will carry a disproportionate weight in the revised judgments. We call this proposition the comparison-revision hypothesis. In Experiments 1-3, we manipulated comparison opportunity by varying the format of the challenge and examined the weights assigned to different inputs in the revised judgments. The results indicate that prior information about the target receives a greater weight under a noncomparative challenge (which provides information only about the target) than under a comparative challenge (which compares the target with a competitor). In contrast, information presented in the challenge receives a greater weight under a comparative challenge than under a noncomparative challenge. Interestingly, when presented in a comparative format, the information contained in the challenge received a relatively disproportionate weight even when the attributes presented in the challenge were less important than those on which the prior target evaluations were based. Results from Experiment 4 suggest that, under certain conditions, even a noncomparative challenge from a superior competitor can provide strong comparison opportunity and thus cause greater revisions in the prior evaluations of the target. Specifically, a greater elaboration of the initial target information and a high degree of commensurability between the target and competitor information jointly promote comparison opportunity and thus cause greater revisions of the prior target judgments. Our findings offer important extensions to previous research on the effects of amount and elaboration of prior target information on subsequent judgment revision. Copyright 1999 Academic Press.

Journal Article↗

PubMed1994

Comparison of various Monte Carlo track structure codes for energetic electrons in gaseous and liquid water.

Cross section for kurbuc, a Monte Carlo track structure code simulating histories of electrons, interaction by interaction, in the energy range of 10 eV to 10 MeV, have been presented. Comparisons have been made for four independent Monte Carlo track structure codes for energetic electrons in gaseous and liquid water. The comparisons have been made in terms of point kernels for interactions and energy absorbed, and frequencies of energy depositions in cylindrical volumes of sizes similar to biological macromolecules. Comparisons have been made for 100 eV, 300 eV, 500 eV, 1 keV, 10 keV and 100 keV monoenergetic electrons. The four electron codes used in this study are moca8b and kurbuc for water vapour and orec and cpa100 for liquid water. A summary of cross sections, used in each code has been presented. The comparisons show similarities and differences in clustering properties of the four codes.

Chromatin↗

PubMed1989

Comparison of the inhalation toxicity of kretek (clove cigarette) smoke with that of American cigarette smoke. I. One day exposure.

The comparative acute toxicity of a branded American cigarette and kreteks (Indonesian cigarettes containing approximately 60% tobacco and 40% ground clove buds) was assessed by exposure of groups of ten male and ten female rats to three different but equivalent (in terms of total particulate matter) concentrations of smoke from each type of cigarette. The smoke was delivered "nose only" using an HRC Rodent Smoking Machine (Mark IV) within a single 1-h period, with a total delivery of 30 min smoke and a 15 min air-breathing period between the two smoke exposures. Comparison of the immediate response to smoke exposure was made by monitoring respiration during exposure and by observation of the animals immediately following exposure. At this level, the only differences observed were more severe signs of smoke intoxication in the American smoke exposed animals which, at least in part, was attributed to the higher concentrations of carbon monoxide (CO) to which these animals were exposed; CO concentrations in the American smoke atmospheres were 2-2.5 times higher than the corresponding kretek smoke atmospheres. Comparison of any delayed response was made by observation and measurement of body weight, food and water consumption for a sub-population maintained for 14 days following exposures. This comparison revealed no differences between the groups which could be attributed to the smoke exposures. Comparison of any lung changes induced were made at two intervals, 24 h and 14 days following smoke exposures. These intervals were selected to provide information on any damage to the lung attributable to the smoke exposures and any subsequent development or repair.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1997

Presurgical localization of abnormal parathyroid glands using a single injection of technetium-99m methoxyisobutylisonitrile: comparison of different techniques including factor analysis of dynamic structures.

Single-tracer methoxyisobutylisonitrile (MIBI) imaging is considered to be a sensitive method for the localization of abnormal parathyroid glands. The aims of this study were to determine which of the analytical techniques described for this method - visual comparison of early (15-min) and late (120-min) images, use of time-activity curves (TACs) generated on regions of interest and factor analysis of dynamic structures (FADS) - corresponds best with surgical findings, and to ascertain the potential overall contribution of presurgical scintigraphy. Fifty-five patients were studied, 34 of whom presented with primary hyperparathyroidism (HPT) and 21 with secondary HPT. After a 925 MBq injection of technetium-99m MIBI, a 40-min dynamic acquisition was performed and static images were acquired at 5, 20, 40 and 120 min using a gamma camera equipped with a pinhole collimator. The dynamic series were submitted to FADS, an attractive non-operator-dependent technique, and TACs were generated on regions of interest after the visual comparison of early and 120-minute images (15'-120'). The presumed localizations of abnormal glands were compared with a sketch drawn by the surgeon. Sensitivity was defined as the percentage of true-positive localizations and was 84.4%, 74% and 65% in adenoma and 76%, 66.6% and 45% in hyperplasia for 15'-120', FADS and TACs, respectively. Surgical accuracy, i.e. the percentage of patients accurately and completely described, was 72%, 56% and 59% in adenoma and 53%, 30% and 22% in hyperplasia for 15'-120', FADS and TACs, respectively. The visual comparison method scored best in all cases. FADS was found to be sensitive in cases of adenoma but was handicapped by more false-positive localizations. TACs were particular inefficient in hyperplasia. With respect to the detection of adenomas, we found a relationship between the gland weight and scintigraphic positivity. This dependence on gland weight was not found in hyperplasia. The poorer results obtained with all techniques for surgical accuracy can be explained by the need for a complete scintigraphic description of all pathological glands found by the surgeon in a patient. This study demonstrates that the 15'-120' visual comparison method is more efficient and less cumbersome than TAC or the attractive FADS technique. However, it was less efficient than neck exploration by an experienced surgeon. Therefore, in our institution, scintigraphic studies are now only requested in selected cases of HPT, usually primary HPT and cases undergoing re-operation.

Adenoma↗

PubMed1992

A survey of multiple sequence comparison methods.

Multiple sequence comparison refers to the search for similarity in three or more sequences. This article presents a survey of the exhaustive (optimal) and heuristic (possibly sub-optimal) methods developed for the comparison of multiple macromolecular sequences. Emphasis is given to the different approaches of the heuristic methods. Four distance measures derived from information engineering and genetic studies are introduced for the comparison between two alignments of sequences. The use of entropy, which plays a central role in information theory as measures of information, choice and uncertainty, is proposed as a simple measure for the evaluation of the optimality of an alignment in the absence of any a priori knowledge about the structures of the sequences being compared. This article also gives two examples of comparison between alternative alignments of the same set of 5SRNAs as obtained by several different heuristic methods.

Algorithms↗

PubMed2003

Comparison of GC-ICP-MS and HPLC-ICP-MS for species-specific isotope dilution analysis of tributyltin in sediment after accelerated solvent extraction.

This study describes a direct comparison of GC and HPLC hyphenated to ICP-MS determination of tributyltin (TBT) in sediment by species-specific isotope dilution analysis (SS-IDMS). The certified reference sediment PACS-2 (NRC, Canada) and a candidate reference sediment (P-18/HIPA-1) were extracted using an accelerated solvent extraction (ASE) procedure. For comparison of GC and LC methods an older bottle of PACS-2 was used, whilst a fresh bottle was taken for demonstration of the accuracy of the methods. The data obtained show good agreement between both methods for both the PACS-2 sediment (LC-ICP-IDMS 828+/-87 ng g(-1) TBT as Sn, GC-ICP-IDMS 848+/-39 ng g(-1) TBT as Sn) and the P-18/ HIPA-1 sediment (LC-ICP-IDMS 78.0+/-9.7 ng g(-1) TBT as Sn, GC-ICP-IDMS 79.2+/-3.8 ng g(-1) TBT as Sn). The analysis by GC-ICP-IDMS offers a greater signal-to-noise ratio and hence a superior detection limit of 0.03 pg TBT as Sn, in the sediment extracts compared to HPLC-ICP-IDMS (3 pg TBT as Sn). A comparison of the uncertainties associated with both methods indicates superior precision of the GC approach. This is related to the better reproducibility of the peak integration, which affects the isotope ratio measurements used for IDMS. The accuracy of the ASE method combined with HPLC-ICP-IDMS was demonstrated during the international interlaboratory comparison P-18 organised by the Comité Consultatif pour la Quantité de Matière (CCQM). The results obtained by GC-ICP-IDMS for a newly opened bottle of PACS-2 were 1087+/-77 ng g(-1) Sn for DBT and 876+/-51 ng g(-1) Sn for TBT (expanded uncertainties with a coverage factor of 2), which are in good agreement with the certified values of 1090+/-150 ng g(-1) Sn and 980+/-130 ng g(-1) Sn, respectively.

Journal Article↗

PubMed2004

A comparison of two factorial designs, a complete 3 x 3 factorial and a central composite rotatable design, for use in binomial response experiments in aquatic toxicology.

Using an amphibian toxicity testing protocol, comparative studies were conducted to assess the predictive precision, degree of similarity of results and efficiency of a central composite rotatable design (CCRD) in relation to a conventional complete 3x3 factorial design. Data were treated with response surface analysis using generalized linear models (glm) and application of profile deviance to generate confidence intervals. Design comparisons were based on studies conducted using the Frog Embryo Teratogenesis Assay-Xenopus (FETAX) protocol to examine the interaction of three toxicants at pH levels ranging from 4.5 to 8.5. Test substances included two commercial herbicide formulations based on glyphosate ([N-phosphonomethyl]glycine) isopropylamine salt (Vision, Rodeo) as well as a polyethoxylated tallow amine surfactant blend (MON 0818), which is a key component of the Vision formulation. The generated models from both the CCRD and the factorial designs produced toxicity estimates similar to each other and to previously published results. Trends were also similar to published results in that the surfactant, MON 0818, was comparatively more toxic than Vision, which was more toxic than Rodeo. Further, all toxicants induced higher mortality under alkaline as opposed to acidic conditions. The CCRD was between 66 and 124% more efficient in the Vision and Rodeo experiments in comparison to the complete 3x3 factorial. Thus, the factorial experiment would have required at least 66% more observations to obtain the same precision. There appeared to be no efficiency gain with the use of the CCRD for MON 0818. The CCRD had tighter confidence intervals in 9 of 12 cases across all test substances. Computer simulations using the experimental data for Vision demonstrated that the LCalpha estimates generated from the 1,000 simulated data sets were very close to the "true" value for both designs. This was based on small bias and mean squared error calculations. Coverage probabilities in both designs were between 91.6 and 95.6%, close to the nominal coverage of 95%. Efficiency comparisons of the simulated Vision data sets demonstrated that the CCRD was more efficient in 93.3% of the comparisons. We suggest that a CCRD using glm and profile deviance for statistical analyses be considered an effective and efficient alternative in toxicity studies where interactive effects are of interest.

Abnormalities, Drug-Induced↗