evidence based practice test #3

narrative reviews

summarize the literature and in some instances include clinical recommendations; limitation: reader must have a great deal of confidence in the author, trusting that the author has done a thorough and unbiased report on the subject 

systematic review

uses a scientific approach to answer a research question by synthesizing existing research rather than collecting new data; secondary research (primary research= individual studies included in the review)

systematic

1) research question is written

2) methodology is defined

3) data is collected

4) results are analyzed

5) findings are reported

abstract

provides summary of review

introduction

presents background/purpose

methods 

sample=number of studies

inclusion and exclusion criteria: studies included in the review 

data collection: databases searched and key words used in the search 

also who collected the data and what information was abstracted 

results

describes how many studies were identified that met the criteria; table made up of summaries of each individual study

discussion

summarizes the results; provides clinical recommendations; limitations acknowledged

replication

multiple studies enhance confidence in the findings because they provide evidence from several perspectives

heterogeneity 

a common criticism of systematic reviews concerns their tendency to synthesize the results of the studies that had substantial differences; particularly problematic when different outcome measures or statistical analyses are used or reported 

study heterogeneity

differences that often exist among studies in terms of the samples, interventions, settings, outcome measures, and other important variables

meta-analysis

quantitative results are combined ; results of similar quantitative studies (i.e. using the same theoretical constructs and measures) are pooled using statistical methods

first step of meta analysis 

calculating an effect size for each individual study 

second step of meta analysis

pool the effect size from all the studies to generate an overall effect

thematic synthesis

qualitative results combined; systematic process used to identify themes from each individual study and then find similar themes in other studies

advantages of meta analysis 

increased statistical power simply by increasing the number of participants when compared with a single study; pooled effect size may provide a more accurate representation of that impact, because it takes into account multiple studies; may be used to try to explain some of the differences between studies 

disadvantage of meta analysis

differences of included studies may make combining results illogical

systematic reviews and practice guidelines

useful tools because they condense large amounts of research evidence and provide direction

descriptive studies

explain health conditions and provide information about the incidence and prevalence of certain conditions within a diagnostic group

predictive studies 

provide information about factors that are related to a particular outcome 

incidence

the frequency of new occurrences of a condition during a specific time period; calculated as the number of new cases during a time period, divided by the total population at risk

prevalence

the number of individuals in a population who have a specific condition at a given point in time, regardless of onset; calculated as the number of cases at a given time point, divided by the total population at risk

incidence and prevalence studies 

help practitioners know how widespread a particular condition is and how likely someone is to develop it; not possible to make conclusions regarding the causation; large samples needed in epidemiological studies result in the use of efficient data collection methods such as surveys 

ex post facto comparisons

cross sectional designs that compare two or more groups, often those with and without a certain condition, at one point in time 

developmental research

longitudinal design used to compare groups

group comparison studies

lack of random assignment and manipulation of the independent variable present potential threats to validity

advantages to survey research

ease with which large amounts of data can be collected, particularly when surveys are administered electronically; opportunity to use random sampling method as it is possible to reach individuals in different geographic locations

response rate

percentage of individuals who return a survey based on the total numbers of surveys administered

response bias

measurement error that creates inaccuracy in the survey results

self reporting issues

desire to present self in a favorable light

cross sectional 

most surveys used in research are __ in nature (i.e gather data at a single point in time) 

study designs to predict an outcome

1) studies that use correlational methods

2) studies using group comparison methods

purpose: identify factors that are most predictive of an outcome

shared variance 

the overlap represents the amount of variance accounted for by the relationship between fatigue and quality of life 

multicollinearity

circumstance in which variables are correlated with one another; two primary types of regression analyses that examine multiple predictors:

1) multiple linear regression

2) multiple logistic regression

multiple linear regression 

used when the outcome is a continuous variable 

multiple logistic regression

used when the outcome and predictors are categorical variable (odds ratio)

odds ratio

probability statistic that determines the likelihood that if one condition occurs, a specific outcome will also occur

case control design

observational, retrospective, cross-sectional study that can be used to answer prognostic research questions concerning which risk factors predict a condition

qualitative thematic synthesis 

the results of multiple qualitative studies may also be synthesized, although this process can be controversial 

practice guidelines

provide recommendations for specific clinical situations (developed my organizations such as AOTA)

strengths of practice guidelines

1) consider the reputation and resources of the organization that creates them

2) time frame within which the practice guideline was developed and published= another important consideration

3) should be transparent about the process used to review and evaluate the evidence

4) best practice guidelines follow the process of a systematic review

5) should undergo a rigorous review process that involves multiple components and many individuals

6) should be stated in a way that practitioners are given information that is helpful in determining whether a recommendation should be adopted in their practices 

complex correlational designs

look at multiple predictors for a single outcome; regression analysis used: to trust results, need large sample; these studies have the advantage of examining the total amount of variance accounted for by multiple predictors and the relative importance of each individual variable as a predictor

Level I

systematic reviews of prospective cohort studies

Level II

individual prospective cohort study

Level III 

retrospective cohort study 

Level IV

case control design

Level V

expert opinion, case study

continuous data

result from a test in which the score can be any value within a particular continuum (ex. range of motion)

discrete data (categorical data) 

classifying individuals or their performance into groups, such as gender or diagnosis; may be numerical values, although the numbers assigned reflect a category more than quantity (i.e manual muscle testing) 

dichotomous data

type of discrete data with only two categories

controversial 

likert scale data=_____ 

norm referenced test

scores are compared with those of other individuals; purpose: discriminate between individuals so as to determine if an individual’s abilities fall within or outside a typical range of abilities

criterion-referenced test

based on a standard or fixed point, which is established by experts, the individual is then tested to determine how his or her performance compares with the established benchmark

reliability 

the stability of a score 

measurement error

the difference between a true score and an individual’s actual score; try to reduce

1) method error

2) trait error

method error

due to testing situation/bias

trait error

when aspects of the test taker, such as fatigue or poor test taking skills, interfere with his or her true score

test reliability 

measured on a continuum, can increase reliability by increasing the number of items on a test; however lengthy tests are often not practical in the clinical setting 

test-retest reliability

estimates stability over time; amount of time between tests is critical; enough time needs to elapse so that the benefits from memory or practice do not influence the results; but not enough time so that history or maturation affects the scores

inter-rater reliability

Different raters come up with similar conclusions; when using a categorical measure, Cohen’s kappa is typically used to assess inter-rater reliability; Kappa depicts the amount of agreement between raters and like the other reliability coefficients, ranges from 0 to 1.0