Misuses of statistics pdf

Research in surgical literature is essential for furthering knowledge, understanding new clinical questions, as well as improving surgical technique yet surgical research provides unique methodology challenges compared to nonsurgical clinical studies 1.

Biostatistics provides clinicians and researchers with the tools necessary to analyze associations and relationships within the data. The type of statistical analysis used, and consequently the data results depend on many factors: appropriate study design, type of data, proper selection and application of statistical methods, distribution of the data, and correct interpretations of the results 23.

Statistics are therefore used to evaluate relationships and trends in data results. Published literature and data help clinicians and researchers deal with the increasing complexity and advancements in medical care such as new treatments, regulations, policies and public safety concerns 4. Surgical education peer-reviewed publications have markedly increased over the last decade 5. The statistical complexity of the research in clinical surgery is also increasing 4.

Statistical methods have since become more complex with a variety of tests and sub-analyses that can be used to interpret, understand and analyze data.

The papers often failed to test for significance when appropriate, quoted probability values without reference to the specific test used, and misused basic statistical techniques Another study assessed orthopedic surgery papers using a validated questionnaire. Although statistical models have become more complex in recent years, basic parametric statistical tests continue to be used at a high rate This paper aims to describe and evaluate the use and misuse of statistical methods and analyses in surgical literature.

We will also provide information on which tests are currently being used, which tests should be used depending on the data and study design, and finally information on how to perform and come up with an appropriate statistical analysis plan for future surgical research. Many factors dictate the type of statistical test used when analyzing research data: study design, research questions and the type of data If the underlying research methods are not appropriately identified prior to creation of an analysis plan, significant mistakes and potential misinterpretation of results are more likely.

The consequence of applying the wrong statistical test ranges from minor, such as a relative shortcoming in methods, to significant, such as nullifying research results and conclusions Broadly, statistical tests are divided into two groups- those that assess differences versus similarities in the data.

The most common type of tests used in research evaluates if differences exists among the data These tests include one sided and two sided tests. A one sided test determines if the statistical difference occurs in only one direction only better, only higher, etc.

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One sided tests are less conservative than two sided tests. To achieve statistical significance with a 2 sided test means that a one sided test of the same type on the same data achieves statistical significance by definition.

The equivalence and non-inferiority tests 1819 evaluate if data is similar.To browse Academia. Skip to main content.

Log In Sign Up. Misuses of statistical analysis in climate research. Hans von Storch. Download Free PDF.

misuses of statistics pdf

Free PDF. Download with Google Download with Facebook or. Download PDF Package. Premium PDF Package. This paper. A short summary of this paper. However, for statistical inference, i.

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Because of these two problems the fundamental question of how much information about the examined process is really available can often hardly be answered. Confusion about the amount of information is an excellent hotbed for methodological insufficiencies and even outright errors.

Some people, and sometimes even peer reviewers, react like Pawlow's dogs when they see a hypothesis derived from data and they demand a statistical test of the hypothesis. See Section 2. Often these basic assumptions are disregarded with the effect that the conclusion of the statistical analysis is void. A standard example is disregard of the serial correlation.

Misuse of statistics in surgical literature

See Sections 2. Sometimes physically meaningful names are attributed to mathematically defined objects. These objects, for instance the Decorrelation Time, make perfect sense when used as prescribed. However, often the statistical definition is forgotten and the physical meaning of the name is taken as a definition of the object -which is then interpreted in a different and sometimes inadequate manner.

It happens again and again that some people expect miracle-like results from advanced techniques. The results of such advanced, for a "layman" supposedly non-understandable, techniques are then believed without further doubts.

Mandatory Testing and the Mexican HatIn the desert at the border of Utah and Arizona there is a famous combination of vertically aligned stones named the "Mexican Hat" which looks like a human with a Mexican hat. It is a random product of nature and not manmade. Can we test the null hypothesis "The Mexican Hat is of natural origin"?

To do so we need a test statistic for a pile of stones and a probability distribution for this test statistic under the null hypothesis. How do we get a probability distribution of t p for all piles of stones p not affected by man?

This condition is fulfilled and we may conclude: The Mexican Hat is not of natural origin but man-made. Obviously, this argument is pretty absurd -but where is the logical error? The fundamental error is that the null hypothesis is not independent of the data which are used to conduct the test. We know a-priori that the Mexican Hat is a rare event, therefore the impossibility of finding such a combination of stones cannot be used as evidence against its natural origin.

The same trick can of course be used to "prove" that any rare event is "non-natural", be it a heat wave or a particularly violent storm -the probability of observing a rare event is small. One might argue that no serious scientist would fall into this trap.Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising.

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Submit Search. Home Explore. Successfully reported this slideshow. We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime. Misuse of statistics. Upcoming SlideShare. Like this presentation? Why not share! Embed Size px. Start on. Show related SlideShares at end.

WordPress Shortcode. Aleena Alvi Follow.Statistics show that the risk of dying from an illness while in the hospital is many times greater than the risk of dying from an illness while at home.

By the same token, there is a strong association between dying and being in bed. While most of us may not be able to precisely identify and explain the logical fallacies implied by this type of statistical reasoning, the nonsense of it is sufficiently apparent so that no one is likely to avoid beds or hospitals in order to prolong his life. Yet the same sort of statistics too often finds its way into the general health literature and mass media where the errors of logic are less apparent and pass unrecognized.

No one would deny the important contributions that the proper use of statistics has made to the advancement of medicine and public health. Epidemics are brought under control, drugs. Some Misuses of Health Statistics. Coronavirus Resource Center. All Rights Reserved. Twitter Facebook Email. This Issue. Edward G. Ludwig, PhD ; John C. Collette, PhD. Save Preferences.

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misuses of statistics pdf

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Misuses of statistical analysis in climate research.

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