Biomedical subjects

William P Fisher

Publications and source records attributed to William P Fisher.

6 recordsLinked to original sources

PubMed2006

Assessing measurement properties of two single-item general health measures.

BACKGROUND: Multi-item health status measures can be lengthy, expensive, and burdensome to collect. Single-item measures may be an alternative. We compared measurement properties of two single-item, general self-rated health (GSRH) questions to assess how well they captured information in a validated, multi-item instrument. METHODS: We administered a general health survey (SF-12V) that included "standard" and "comparative" forms of a GSRH. We repeated the survey two weeks later to the same 75 medically stable outpatients to test for GSRH reproducibility, reliability, and validity using SF-12V Physical Functioning and Emotional Health subscales as a reference. RESULTS: At each survey administration, the two GSRH questions demonstrated good alternate forms reliability (first administration: r = 0.74, p < 0.001; second administration: r = 0.74, p < 0.001) and good reproducibility ("standard": ICC 0.69; "comparative": ICC 0.85). Both GSRH items correlated with physical functioning ("standard": r = 0.66; "comparative": r = 0.56) and emotional health measures ("standard": r = 0.65; "comparative": r = 0.59). Mean subscale measures associated with responses in each GSRH category were significantly different (ANOVA, p < 0.001), indicating strong discriminant scale performance. CONCLUSIONS: Our single-item, GSRH questions demonstrated good reproducibility, reliability, and strong concurrent and discriminant scale performance with an established health status measure.

Adult↗

PubMed2005

Daredevil barnstorming to the tipping point: new aspirations for the human sciences.

Aviation history provides an apt metaphor for the state of Rasch measurement practice, and its potential future. Flying was initially widely believed to be nothing but a spectacular and dangerous fad. Few saw in it any potential for the huge industry that it is today. The current state of Rasch measurement practice is quite akin to daredevil barnstorming in that the field is focused on isolated demonstrations of disconnected technical effects. Only when the analogues of air traffic control, airports, support staff, training programs, textbooks, and partner industries (hotels, restaurants) are in place will Rasch measurement come into its own as the technical medium of a widespread industry. The point at which current practice tips into a new paradigm depends on the realization of operationally validated theory in a supportive social context. The paper closes with speculations on what crossing Rasch measurement's tipping point might entail.

Aviation↗

PubMed2005

Evaluation of the Diabetes Self-Care Scale.

The purpose of this study was to evaluate the psychometric properties of the Diabetes Self-Care Scale (DSCS). A convenience sample of 175 adults with diabetes who met the inclusion criteria from a local hospital in southern Louisiana participated in this study. Data from a pilot study with 50 respondents were also used to calibrate the instrument. The analysis tested the hypothesis that the difference between any respondent's agreement with an item and the difficulty presented by that item is equal to the natural logarithm of the odds of a response. Results indicated that respondent separation reliability is acceptable (.80) and item separation reliability is high (.99). All 35 items measure a single construct of diabetes self-care. Construct validity was supported by the meaningfulness of the item endorsability order and by the consistency of that order across respondents. Seven recommendations for modification of the instrument, future research, and practice are proposed.

Adolescent↗

PubMed2004

Calibrating the genome.

PURPOSE: This project demonstrates how to calibrate different samples and scales of genomic information to a common scale of genomic measurement. MATERIALS AND METHODS: 1,113 persons were genotyped at the 13 Combined DNA Index System (CODIS) short tandem repeat (STR) marker loci used by the Federal Bureau of Investigation (FBI) for human identity testing. A measurement model of form ln[(P(nik))/(1-P(nik))] = B(n)-D(i)-L(k) is used to construct person measures and locus calibrations from information contained in the CODIS database. Winsteps (Wright and Linacre, 2003) is employed to maximize initial estimates and to investigate the necessity and sufficiency of different rating classification schema. RESULTS: Model fit is satisfactory in all analyses. Study outcomes are found in Tables 1-6. CONCLUSIONS: Additive, divisible, and interchangeable measures and calibrations can be created from raw genomic information that transcend sample- and scale-dependencies associated with racial and ethnic descent, chromosomal location, and locus-specific allele expansion structures.

Alleles↗

PubMed2003

Are physicians equipped to address the obesity epidemic? Knowledge and attitudes of internal medicine residents.

BACKGROUND: To analyze whether internists are suited for their role in treating the growing numbers of obese patients, we surveyed residents about their knowledge and attitudes regarding obesity. Previous assessments have not analyzed familiarity with obesity measurement tools or the correlation between knowledge and attitudes. METHODS: We administered a survey to 87 internal medicine residents in two urban, university-based residency programs. RESULTS: Almost all respondents understood the medical consequences of obesity, but 60% did not know the minimum BMI for diagnosing obesity, 69% did not recognize waist circumference as a reasonable measure of obesity, and 39% incorrectly reported their own BMI. Although nearly all respondents agreed that treating obesity was important, only 30% reported treatment success. Forty-four percent felt qualified to treat obese patients, and 31% reported treatment to be futile. Knowledge and attitudes were not correlated. Rasch analysis of knowledge and attitude subscales showed satisfactory model fit and item reliability of at least 0.96. CONCLUSIONS: Despite solid knowledge of the comorbid conditions associated with obesity, residents have a poor grasp of the tools necessary to identify obesity. They also have negative opinions about their skills for treating obese patients. Residency training not only must improve knowledge of obesity measurement tools but also must address physicians' negative attitudes toward obesity treatment.

Adult↗

PubMed2002

Evaluation of the diabetes self care scale: an illustration of the Rasch model of measurement.

This pilot study illustrates the use of a Rasch measurement model to evaluate the psychometric properties of the Diabetes Self Care Scale (DSCS). A convenience sample of 50 adults with diabetes at two local hospitals (one for profit and one public) in southern Louisiana responded to the survey questions. The instrument is comprised of 27 items and 6 rating categories. The Bigsteps Rasch measurement software was used for all analyses. Results indicated that respondent separation reliability was low (0.63), but item separation reliability was satisfactory (0.91). Internal validity was supported. Twenty-six items measure a single construct of diabetes self care. Construct validity was supported by the meaningfulness of the item difficulty order and by the consistency of that order across respondents. Rating scale analysis revealed that middle categories were not distinct steps in the progression of increasing diabetes self care. In addition to deleting an item producing inconsistent responses and combining adjacent categories (categories 1 and 2, and categories 3, 4, and 5), four recommendations for future research are provided.

Adult↗