RE: Interrater reliability
Allen, You might refer to this paper. Burry-Stock, J. A., Shaw, D. G., Laurie, C., & Chissom, B. S. (1996). Rater agreement indexes for performance assessment. Educational & Psychological Measurement, 56, 251-262. Peter Chen -Original Message- From: Allen E Cornelius [SMTP:[EMAIL PROTECTED]] Sent: Wednesday, January 19, 2000 11:22 AM To: [EMAIL PROTECTED] Subject:Interrater reliability Stat folks, I have an interrater reliability dilemma. We are examining a 3-item scale (each item scored 1 to 5) used to rate compliance behavior of patients. Two separate raters have used the scale to rate patients' behavior, and we now want to calculate the interrater agreement for the scale. Two problems: 1) The majority of patients are compliant, and receive either a 4 or 5 for each of the three items from both of the raters. While this is high agreement, values for ICC are very low due to the limited range of scores. Are there any indexes that would reflect the high agreement of the raters under these conditions? Perhaps something that accounts for the full range of the scale (1 to 5)? 2) The dataset contains a total of about 100 observations, but there are multiple observations on the same patients at different times, probably about 5 to 6 observations per patient. Does this repeated assessment need to be accounted for in the interrater agreement, or can each observation be treated as independent for the purpose of interrater agreement? Any suggestions or references addressing this problem would be appreciated. Thanks. Allen Cornelius
Occupational safety award
Sorry for cross-posting. Peter Chen IEA/Liberty Mutual Prize Applications are now being accepted for the 2000 International Ergonomics Association (IEA)/Liberty Mutual Prize in Ergonomics and Occupational Safety. This $5,000 award recognized individuals who have made significant contributions to the reduction or prevention of work-related injuries and/or to the advancement of theory, understanding, and development of occupational safety research. In addition, the Liberty Mutual Medal in Ergonomics and Occupational Safety (awarded every three years) will be given in 2000. This honor is given to the best of three Liberty Mutual Prize awardees from the previous three years and consists of a medal and $20,000. a) Anything that is concerned with accidents or prevention, injury prevention, rehabilitation or return to work in any discipline including epidemiology, biology, cell biology, ergonomics, human factors, biomechanics, rehabilitation engineering, etc. b) This is for unpublished work at the time of submission, thus, outstanding papers that have been submitted, and even accepted in journals, but have not yet appeared are appropriate submission items. c) Clearly, although the requirement is for unpublished, the expectation is that the winning award will form the basis of an outstanding published paper in a premier journal. d) Applicants are not necessarily members of the IEA or any of its constituent groups. e) This is for a research paper. Applications, unless they are intervention research, are not eligible. To be considered for the Liberty Mutual Prize, candidates must submit a letter of application and five copies of an original, previously unpublished research paper relevant to the field of occupational safety and ergonomics. An international review committee will select the winning contribution. The prize and medal will be presented at the IEA/HFES 2000 Congress in San Diego. The deadline for submission is March 1, 2000. For further information, contact Martin Helander, School of Mechanical and Production Engineering, Nanyang Technological University, Singapore 639798; +65-790-6398, fax +65-791-1859; [EMAIL PROTECTED] Applicants will be notified by June 2000.
RE: Position Announcement
Dear Colleagues, Sorry for cross-posting for the Position Announcement. Peter Chen Liberty Mutual Research Center for Safety and Health Researcher We are seeking an experimentalist with expertise in transportation psychology. Individuals with interests in any area of transportation psychology will be considered. Those with interests in safe driving interventions, driver selection, and intelligent transportation system (ITS) technologies are especially encouraged to apply. Strong methodological skills and the ability to conduct original, scholarly research are more important than specific area of interest. The successful candidate will possess a background in psychology or related fields (e.g., human factors). Ph.D. or equivalent is required. Recognized by scientific awards from around the world for contributions to the improvement of workplace safety and health, the Research Center employs a multidisciplinary, team-oriented staff of researchers representing fields including: biomechanics, cognitive psychology, industrial/organizational psychology, epidemiology, tribology, physiology, engineering, sociology, biostatistics, and the clinical sciences. The Research Center is located on 86 acres of woodland 25 miles west of Boston, MA. Significant collaborations exist with Harvard University, Texas Tech University, Shanghai Medical University (PRC), the University of Aberdeen (UK), and the Health and Safety Laboratories of the Health and Safety Executive (UK). The Research Center is fully funded and committed to peer-reviewed publication of all its findings. An outstanding driving range and opportunities for further laboratory development are available. For more information about the Liberty Mutual Research Center see our website at http://www.libertymutual.com/research. Interested individuals should submit curriculum vitae, reprints/preprints, and a statement of research background and interests to the attention of: James E. Klock Director of Operations Liberty Mutual Research Center for Safety and Health 71 Frankland Road, Hopkinton, MA 01748 USA === This list is open to everyone. Occasionally, less thoughtful people send inappropriate messages. Please DO NOT COMPLAIN TO THE POSTMASTER about these messages because the postmaster has no way of controlling them, and excessive complaints will result in termination of the list. For information about this list, including information about the problem of inappropriate messages and information about how to unsubscribe, please see the web page at http://jse.stat.ncsu.edu/ ===
Job openings
Dear Colleagues, My colleagues asked me to distribute the job announcement to whomever may be interested in. Please direct any inquiry pertaining to the position to Dr. Mary Lesch. Happy Holidays, Pete Chen Liberty Mutual Research Center for Safety and Health, are hiring one or more junior investigators to conduct research in the areas of occupational safety and health. The positions require either one or two-year commitment. These positions, however, can be turned into permanent positions. Experience Desired: Open Degree Level Desired: Ph.D. or ABD in Industrial/Organizational Psychology or related areas Area of Expertise: Open When Available: Open In addition to subject knowledge expected skills include: advanced statistical analyses, research design, statistical software (especially SAS), interpersonal and team skills, and oral and written communications in English. The Research Center's primary goal is to determine the causes of accidents and injuries, then identify and validate interventions. The objective is to drive down the incidence of occupational injuries and reduce the disabilities arising from those that do occur. The Center's research incorporates a wide range of occupational safety and health concerns as they affect various industries such as construction, transportation, manufacturing, hospitality, retail and high technology. For further information, please visit our website at http://www.libertymutual.com/research/index.html The jobs are located in Hopkinton, Massachusetts, which is about 30 miles west of Boston. Please send your resume/CV and cover letter to [EMAIL PROTECTED] = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
standard error of r and expected r
Dear Colleagues,
I have a few questions related to Pearson r when rho = zero.
First question,
I recall E(R-square)=k/(n-1), where k=numbers of predictor, and n=sample
size. Is it a correct expression?
Could you advise me the source of this formula?
Second question,
Assuming the above formula is correct, E(R-square)= 1/(n-1), when there is
one predictor.
(a) The above result can be rewritten to E(r-square) = 1/(n-1) or E(r) =
Sqrt {1/(n-1)}.
(b) As demonstrated elsewhere, Pearson r is an unbiased estimator only when
rho =0 or rho=1. Therefore, E(r) = rho = 0.
The statements of (a) and (b) are not consistent! Any comment?
Third question,
According to R. A. Fisher (1915), the standard error of Pearson r
approximates sqrt {(1 - rho-square)/n} or sqrt (1/n) when n increases.
When testing if Pearson r is different from zero with small sample sizes,
the standard error chosen in the t-test is sqrt {(1 - rho-square)/(n-2)} or
sqrt {1/(n-2)}. Where is the source about the standard error used in the
t-test?
Fourth question,
Following question 3, given the null hypothesis rho=0, why do we use sample
Pearson r, instead of rho, to calculate the standard error, sqrt {(1 -
r-square)/(n-2)}? It is not my impression that this t-test is conducted
based on a posterior probability distribution.
Fifth question 5,
Why don't we just use Fisher's z z-test to conduct the above hypothesis?
Thanks for your inputs.
Best,
Peter Chen
========
Peter Chen
Department of Psychology
Colorado State University
Fort Collins, CO 80523-8033
[EMAIL PROTECTED] (home)
[EMAIL PROTECTED] (office)
Office Voice: 970-491-2143
Office Fax: 970-491-1032
Home Voice: 970-266-8927
http://www.colostate.edu/~chenp
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