Re: CIs for adjusted rates
"Scheltema, Karen" wrote: > I have complication rates for a given procedure. I was thinking of using > indirect standardization as a method of risk adjustment given that some > doctors see more complex patients. What I can't figure out is how I would > go about calculating a 95% CI after the risk adjustment. Any pointers would > be greatly appreciated. > > Karen Scheltema, M.A., M.S. What's the variablility you're trying to model: variability in the patient's risk of complications or variability in the physician's case mix? Indirect standardization is set up to handle the latter. Is this what you really want? You're going to have to be clearer about the hypothesis that you're testing. You didn't ask, but I would be surprised if you got exactly what you expected out of complication data. They tend to be poorly collected so it's hard to eliminate the influence of differential coding practices. --Robert Chung = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: CIs for adjusted rates
At 08:35 AM 11/21/01 -0600, Scheltema, Karen wrote: >I have complication rates for a given procedure. I was thinking of using >indirect standardization as a method of risk adjustment given that some >doctors see more complex patients. What I can't figure out is how I would >go about calculating a 95% CI after the risk adjustment. Any pointers would >be greatly appreciated. why not define a group of doctors or cases as ... less complex patients .. and more complex patients ... and do the confidence intervals separately (you might do one overall interval to see how it compares to the two separate ones ... perhaps there is little difference) one problem i do see is that ... some doctors deal with both so, the two classes above (less complex, more complex) are not totally independent >Karen Scheltema, M.A., M.S. >Statistician >HealthEast >Research and Education >1700 University Ave W >St. Paul, MN 55104 >(651) 232-5212 (phone) >(651) 641-0683 (fax) >[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/ >= _ dennis roberts, educational psychology, penn state university 208 cedar, AC 8148632401, mailto:[EMAIL PROTECTED] http://roberts.ed.psu.edu/users/droberts/drober~1.htm = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
CIs for adjusted rates
I have complication rates for a given procedure. I was thinking of using indirect standardization as a method of risk adjustment given that some doctors see more complex patients. What I can't figure out is how I would go about calculating a 95% CI after the risk adjustment. Any pointers would be greatly appreciated. Karen Scheltema, M.A., M.S. Statistician HealthEast Research and Education 1700 University Ave W St. Paul, MN 55104 (651) 232-5212 (phone) (651) 641-0683 (fax) [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/ =
Re: CIs
Dennis Roberts wrote: > > it seems to me that the notion of a confidence interval is a general > concept ... having to do with estimating some unknown quantity in which > errors are known to occur or be present in that estimation process > > in general, the generic version of a CI is: > > statistic/estimator +/- (multiplier) * error > > the multiplier will drive the amount of confidence and, error will be > estimated by varying processes depending upon the parameter or thing you > are estimating > One issue for individual observations is that one might use a prediction interval or a tolerance interval depending on the exact research question. One looks more like a confidence interval, the other less. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: CIs
Dennis Roberts wrote: > > it seems to me that the notion of a confidence interval is a general > concept ... having to do with estimating some unknown quantity in which > errors are known to occur or be present in that estimation process > > in general, the generic version of a CI is: > > statistic/estimator +/- (multiplier) * error Dennis, this is just not so. Even some familiar and widely-used confidence intervals like the sign interval do not follow this pattern. I think I understand what you are trying to say; there is a general concept of interval estimator, and within that a special class which are obtained by specifying a point estimator for a parameter and some multiple of its spread. *Some* confidence intervals - the most familiar, I will agree - are of this type. But not all of these are confidence intervals and not all CI's are of this type. So please let us not abuse the word "confidence interval" for things that generally aren't. -Robert Dawson = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
CIs
it seems to me that the notion of a confidence interval is a general concept ... having to do with estimating some unknown quantity in which errors are known to occur or be present in that estimation process in general, the generic version of a CI is: statistic/estimator +/- (multiplier) * error the multiplier will drive the amount of confidence and, error will be estimated by varying processes depending upon the parameter or thing you are estimating what we might want to estimate in a regression setting is what one particular person might do on a future outcome variable, like college gpa, given that we know what THAT person has achieved on some current variable (high school gpa) ... if we are interested in this specific person, then error will be estimated by some function of HIS/HER variation and that will be factored into the above generic equation as error ... this would be what jon cryer rightfully called a prediction interval ... BUT, it still fits within the realm of the concept of a CI in other regression cases, we might not be interested in estimation for one specific individual on the criterion given that individual's score on the current variable, but rather what is the expected MEAN criterion value for a group of people who all got the same current variable value ... in this case, error is estimated by some function of the group on the current variable ... and this is what in regression terms is called a confidence band or interval ... but, the concept itself is no different than the prediction interval ... what IS different is what is considered error and how we estimate it when we use a sample mean to estimate some population mean, we have the same identical general problem ... since we use the sample mean as the estimator and, we have a way of conceptualizing and estimating error (sampling error of the mean) in that case BUT, we still use the generic formula above ... to build our CI in all of these cases, there is a concept of what error is and, some method by which we estimate it and, in all these cases we use some given quantity (statistic/estimator) to take a stab at an unknown quantity (parameter/true criterion) and we use the estimated error around the known quantity as a fudge factor, tolerance factor, a margin of error factor ... when making our estimate of the unknown quantity of interest all of these represent the same basic idea ... only the details of what is used as the point estimate and what is used as the estimate of ERROR of the point estimate ... change also, in all of these cases whether it be in regression work or sampling error (of means for example) work ... we still attach a quantity ... a percentage value ... to the intervals like we have created when estimating the unknown and, as far as i can tell, we interpret that percentage in the same identical way in all of these cases ... with respect to the long run average number or percentage of "hits" that our intervals have of capturing the true value (parameter or true criterion value) i am more than willing to use different terms to differentiate amongst these different settings ... such as in regression when you are inferring something about an individual ... or a group of individuals (though even here, i think we could select better differentiators than we currently use ... like personal interval versus group interval) ... but overall, all of these are variations of the same notion and fundamental idea IMHO of course _ dennis roberts, educational psychology, penn state university 208 cedar, AC 8148632401, mailto:[EMAIL PROTECTED] http://roberts.ed.psu.edu/users/droberts/drober~1.htm = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
News from Current Index to Statistics (CIS)
[apologies for cross-posting] NEWS FROM THE CURRENT INDEX TO STATISTICS A new informational web site has been initiated for the Current Index to Statistics. Please view it at http://www.statindex.org (The query web site is still at http://query.statindex.org) We are pleased to announce the following news about CIS. Details for each of these items are posted on the web site under the heading "CIS News: Other Current News and Announcements". You can also write to [EMAIL PROTECTED] to request more details. (1) QUERY WEB SITE: The CIS query web site serves subscribers to the database, providing a centralized search engine. As a service to the statistics profession, CIS also sponsors FREE access to a limited version of the database, including records up to and including 1991. (2) NEW ABSTRACTING EDITOR APPOINTED: George Styan has been appointed as CIS Abstracting Editor. (3) SEARCH FOR NEW DATABASE EDITOR: We have begun a search for the next CIS Database Editor. This editor is in charge of assembly and quality control of the CIS database, working in cooperation with Professor Styan. (4) SEEKING CONTRIBUTING EDITORS IN ALL FIELDS: CIS seeks new volunteer Contributing Editors to extract bibliography on articles with significant statistical content from journals other than our core of statistical and methodological journals. We depend on these contributors to improve our coverage of important statistical applications and methodological advances in a variety of disciplines. Alan Zaslavsky Chairman, CIS Management Committee === 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/ ===
