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Evidence-Based Practice: Step 3

A tutorial on evidence-based practice.

Steps in the Process

  • Step 1: FORMULATE an answerable question

    The first step in this tutorial helps you to refine your question by defining your clinical problem using a process called PICO. Through this process you will create an “answerable question”. This process will facilitate your search by helping you to identify keywords specific to the patient population, intervention, comparison group and outcomes that are appropriate to your patient care inquiry.

     

  • Step 2: SEARCH FOR the best evidence using the keywords from your PICO question

    The second step in this tutorial helps you to search for an evidence-based answer to your question using the keywords from your PICO question. Through the process you will become aware of four different types of information resources you can use in your search.

     

  • Step 3: ASSESS the validity and usefulness of the search results

    The third step in this tutorial helps you to evaluate your search results. Through this process you will identify the studies which are valid and useful to your question, and then identify and compare the study conclusions. If there are conflicting results, you must look at the evidence to find explanations for the differences and resolve them.

     

  • Step 4: APPLY the evidence

    The fourth step in this tutorial helps you to apply the evidence to your clinical scenario. Through this process you will determine if the evidence can be extrapolated to your patient and then communicate with your patient to make an informed decision.

    • Step 3: ASSESS the validity and usefulness of the search results

    vidence-Based Practice Tutorial

    If you were able to find information that answered your question using any of the top two pyramid level resources in Step 2 (i.e. Summaries of the Evidence and Critically Appraised Research sites) then the evidence you have found has already been assessed. You can skip Step 3 of this tutorial and move onto Step 4. Continue with Step 3 if you found information using the bottom two pyramid level resources (i.e. Individual Research Studies and Textbooks).


    There are three basic questions that need to be answered for every type of study:

    I. Are the results in the study valid?
    II. What are the results?
    III. Will the results help me in caring for my patients?

    The following specific questions are taken from How to Get Started from the Centre for Health Evidence at the University of Alberta and pertain to studies related to Therapy, Diagnosis, Harm and Prognosis.


    Therapy
    I. Are the results of the study valid?
  • Was the assignment of patients to treatments randomized?
  • Were all patients who entered the trial properly accounted for and attributed at its conclusion?
  • Was followup complete?
  • Were patients analyzed in the groups to which they were randomized?

    II. What were the results?
  • How large was the treatment effect?
  • How precise was the estimate of the treatment effect?

    III. Will the results help me in caring for my patients?
  • Can the results be applied to my patient care?
  • Were all clinically important outcomes considered?
  • Are the likely treatment benefits worth the potential harms and costs?


    Diagnosis
    I. Are the results in the study valid?
  • Was there an independent, blind comparison with a reference standard?
  • Did the patient sample include an appropriate spectrum of patients to whom the diagnostic test will be applied in clinical practice?

    II. What are the results?
  • Are likelihood ratios for the test results presented or data necessary for their calculation provided?

    III. Will the results help me in caring for my patients?
  • Will the reproducibility of the test result and its interpretation be satisfactory in my setting?
  • Are the results applicable to my patient?
  • Will the results change my management?
  • Will patients be better off as a result of the test?


    Harm
    I. Are the results of the study valid?
  • Were there clearly identified comparison groups that were similar with respect to important determinants of outcome, other than the one of interest?
  • Were the outcomes and exposures measured in the same way in the groups being compared?
  • Was follow-up sufficiently long and complete?

    II. What are the results?
  • How strong is the association between exposure and outcome?
  • How precise is the estimate of the risk?

    III. Will the results help me in caring for my patients?
  • Are the results applicable to my practice?
  • What is the magnitude of the risk?
  • Should I attempt to stop the exposure?


    Prognosis
    I. Are the results in the study valid?
  • Was there a representative and well-defined sample of patients at a similar point in the course of the disease?
  • Was follow-up sufficiently long and complete?
  • What are the results?
  • How large is the likelihood of the outcome event(s) in a specified period of time?
  • How precise are the estimates of likelihood?

    II. Will the results help me in caring for my patients?
  • Were the study patients similar to my own?
  • Will the results lead directly to selecting or avoiding therapy?
  • Are the results useful for reassuring or counseling patients?
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