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99 Cards in this Set
- Front
- Back
Cohort characteristics
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-A group of people who share a common characteristic or experience within a defined period
-Not randomly selected, but rather identified/selected for a particular reason -Longitudinal observation of the cohort occurs through time, and data is collected at regular intervals (thus reducing recall error). |
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The "case" in case-control study means
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The case is a cohort of people with a common experience (typically a particular diagnosis)
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The "control" in a case-control study means
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The control (or comparison) group: another group that is similar in characteristics to the case group, but does not demonstrate the common experience or does not have the diagnosis of interest
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prospective cohort studies characteristics
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-Outcomes have not yet occurred as study begins.
-Time consuming, expensive -More valid information on exposure -Measurements on potential confounders |
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retrospective cohort studies characteristics
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-Outcomes have already occurred as the study begins.
-Quick, cheap -Appropriate to examine outcome with long latency periods -Admission to exposure data -Difficult to obtain information of exposure -Risk of confounding |
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selection bias in cohort studies
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-Non-response during data collection
-Losses to follow up |
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Misclassification on exposure or event bias in cohort studies
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-Random
-Systematic |
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Confounder bias in cohort studies
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Difference in other risk factors between exposed and non-exposed groups
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Strengths in Cohort study
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-Rare exposure
-Examine multiple effects of a single exposure -Minimizes bias in the exposure determination -Direct measurements of incidence of the disease |
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Strengths in case-control study
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-Quick, inexpensive
-Well-suited to the evaluation of diseases with long latency period -Rare diseases -Examine multiple etiologic factors for a single disease |
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limitations in cohort studies
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-Prospective: Expensive and time consuming
-Retrospective: Inadequate records -Validity can be affected by losses to follow-up |
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limitations in case-control studies
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-Incidence rates cannot be estimated unless the study is population based
-Selection bias and recall bias |
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Design of case-control studies
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-investigator selects cases with the “disease” and appropriate controls without the “disease” and obtains data regarding past exposure to possible etiologic factors in both groups
-investigator then compares the frequency of exposure of the two groups |
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2 challenges of case-control studies
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-Recall bias in the case group;
-Finding a control group with matching characteristics |
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3 qualities needs for selection of controls in case-control studies
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-Comparability is more important than representativeness in the selection of controls
-The control should be at risk of the disease -The control should resemble the case in all respects except for the presence of disease (and any as yet undiscovered risk factors for disease) |
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Comparability vs. Representativeness in case-control studies
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Usually, cases in a case-control study are not a random sample of all cases in the population. And if so, the controls must be selected in the same way (and with the same biases) as the cases.
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selection bias in case-control studies
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-Non-response
-Detection bias *cases and controls are identified not independently of the exposure |
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observation bias in case-control studies
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Recall Bias: Cases are more likely to remember exposure than controls
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For Rehab studies, if the model explains more than __________ of the variance, it is a pretty good model
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60%
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Prognosis: predicting outcomes characteristics
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Descriptive and exploratory studies (case-control, cohort, cross-sectional, and to a lesser degree, case series and case reports) can provide information about variables that inform our ability to make predictions about groups and/or individuals
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Prognosis studies internal validity considerations
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-Single site or multi-site? More sites is better, because it enhances generalizability
-Is there a defined, representative sample of patients? -Were participants recruited at a common point/stage in the disease/condition? This is optimal, however, not always possible. If this is the case, the researchers should address how they managed this (use of case-control design is a good way to address this) -Were participants free of the outcome of interest? Depending on what is being studied, this may not always be feasible; be attentive to how the researchers manage this |
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internal validity bias in prognosis studies
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-Were the individuals collecting the outcome measures blinded to the status of the prognostic factors in each subject?
-Does the sample include subgroups of patients for whom prognostic estimates will differ? If yes, what are they, and are they addressed in the data analysis? |
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Clues for determining prognosis studies
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-Purpose should involve looking at different variables and predicting an outcome
-Methods and/or data analysis will include linear regression (a.k.a. structural equation modeling) |
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Clues for determining intervention studies
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-Purpose is looking at effectiveness
-Methods and/or data analysis will include t-tests, ANOVAs, or some other type of comparison analysis |
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diagnostic test definition
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Any assessment that provides measurement of function to the therapist and provides information used in clinical decision-making
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types of diagnostic tests
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-These may be tests that the therapist directly performs to measure function
-These may be tests that use equipment to measure function -These may be standardized tests -These may be “differential diagnosis” tests, conducted to rule-in or rule-out a pathology or diagnosis |
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Measures of accuracy for diagnostic tests
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-Qualities of the design, administration, and interpretation of quantitative tests for measurement of variables
-Reliability – remember this is a quality of a test, not a study -Sensitivity -Specificity -Positive predictive value -Negative predictive value |
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how accuracy of clinical tests is determined
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-Few, if any clinical tests in the rehabilitation sciences are perfect
-The accuracy (“truth”) of the test is determined against a reference standard (a.k.a. “gold standard”) |
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Why not just use the reference standard?
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-cost
-efficiency |
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sensitivity definition
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Sensitivity is “the proportion of people with a disease that have a positive test result” (p. 134).
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specificity definition
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Specificity is “the proportion of people without a disease that have a negative test result” (p. 134).
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positive predictive value definition
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Positive predictive value is the proportion of people who test positive who actually have the diagnosis. (In this context, “disease,” “pathology,” and “diagnosis” have the same meaning.)
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negative predictive value definition
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Negative predictive value is the proportion of people who test negative who actually do not have the diagnosis.
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value for good sensitivity and good specificity
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70% or higher is very good sensitivity
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test with high sensitivity is good at
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A test with high sensitivity is good at ruling out a pathology because we can trust a negative result (few false negatives).
SNout |
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a test with high specificity is good at
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is good at ruling in a disorder because we can trust a positive result (there are few false positives).
SPin |
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positive predictive value is the chance that
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The chance that a positive test result will be correct
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Negative Predictive Value is the chance
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The chance that a negative test result will be correct
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Likelihood ratios characteristics
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-Rarely given in occupational therapy or physical therapy research
-can calculate them, though, if we know sensitivity and specificity -Fairly powerful tests if: Positive likelihood ratio > 10 Negative likelihood ratio < 0.1 |
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Critical Appraisal of Studies about Diagnostic Test(s) considerations
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-Clearly-stated purpose
-Demonstrates external and internal validity -Appropriate participant selection and sampling -Avoids/minimizes bias -Study was sensible -Appropriate analysis and interpretation of statistics -Clinical bottom-line… does this study inform your practice? |
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Levels of evidence in qualitative studies
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-Meta-syntheses of related qualitative studies
-Group studies with more rigor -Group studies with less rigor -Single informant |
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Relationship between qualitative studies and Wizard of Oz
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-I don't know
-Chris distracted me and got me in trouble -Chris is a bad influence |
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Key concept of qualitative research
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The experience is explained and described by the participants and they, not the researcher, provide the framework for what is important in that context
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Goal of qualitative research
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Development of concepts which help to understand social phenomena in natural (rather than experimental) settings, giving due emphasis to the meanings, experiences, and views of all the participants
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Qualitative Research Methodology Defined
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Disciplined enquiry examining the personal meanings of individuals’ experiences and actions in the contexts of their social environments
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Three Strategies for Mixed Methods Design in qualitative research
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1. sequential
2. concurrent 3. transformative |
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sequential strategy characteristics
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-Elaborate for expand findings of one method
-Either order works |
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concurrent strategy characteristics
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-for comprehensive analysis
-Collects data simultaneously -Nests one form of data collection procedure to analyze different questions or levels |
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transformative strategy characteristics
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-Uses theory as overarching perspective
-Can use either sequential or concurrent approach to data collection |
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qualitative research design characteristics
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-Research question determines methodology
-Primary purpose Basic, applied, evaluation, action -Focus of study Breadth, depth, tradeoffs -Units of analysis Individuals, groups, program, critical incidents, life history, demographic groups, time periods |
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3 design traditions of qualitative research
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1. ethnography
2. phenomenology 3. grounded theory (table slide 38) |
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ethnography focus
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What is the culture of this group?
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phenomenology focus
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What is the essence of lived experience of this phenomenon?
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grounded theory focus
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What theory emerges from analysis grounded in fieldwork / data?
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QUALITATIVE – PURPOSIVE SAMPLING characteristics
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-Depth
-Purposive -Information –rich cases *Learn most about issue of interest from those from whom you can learn the most *Empirical insights and in-depth understanding of study |
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QUALITATIVE – PURPOSIVE SAMPLING sample size
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-NO RULES
-Continue to collect data to point of saturation |
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Methods of qualitative data collection
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1. Interview
A. Individuals B. Groups (focus group) 2. Observation A. As participant B. As observer 3. Document Review |
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Data for interviews
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verbatim transcriptions as written text
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Interview quality of data depends on
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skill of interviewer
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Types of interviews
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-Informal conversational
-Semi-structured using interview guide -Standardized open-ended -Closed, fixed-response interview |
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Observation describes
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Describe the setting, activities, participants, and meanings
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Data for observation
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-Format – live / video
-Field notes = detailed descriptions of people, contexts, actions, etc. observed -Reflexive notes or journal = researcher's emergent thoughts & feelings -Non-occurrences |
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Document review characteristics
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-Document and artifact review
*Provide differing perspectives -Sources *Personal (e.g. diaries) v. Official (e.g. press releases) *Restricted access (e.g. minutes) v. open access (e.g. company reports, medical records) -Criteria (Willmott) *Authenticity, accuracy, representativeness -Data = excerpts from documents; quotes |
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Data codes definition
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-Tags or labels assigned to data to catalogue key concepts while preserving context
-May be done by single researcher who collected data or by an interdisciplinary team |
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Data Codes are a formal way to
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-Organize data
-Find links within and between data |
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Coding Data characteristics
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-Coding must be rich – if oversimplified or dissociated from context, analysis will lack insights
-Codes may be purely inductive, deductive, or a combination of each -Iterative process of reviewing text line by line for codes and refining them -Completed collection and analysis when you reach “data saturation” |
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Types of codes
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1. descriptive codes
2. interpretive codes 3. pattern codes |
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Descriptive codes characteristic
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Name chunks of data with little interpretation
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Interpretive codes characteristic
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Attach causes or motive
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Pattern codes characteristic
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Inferential and explanatory
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Sources of codes
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-Inductive or emergent codes
*Often use participants’ words or phrases as codes or themes -Deductive or codes from theory or literature |
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Phenomenological Analyses characteristics
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-Highlight key phrases to derive codes
-Organize codes into meaningful clusters or categories -Collapse categories to develop themes |
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Role of Qualitative Studies in rehabilitation Research
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-ID's what really matters to patients [and providers], -detects obstacles to changing performance
-explains why improvement does and does not occur -can bring to light complex processes -provide understanding for processes |
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Qualitative Studies in Rehabilitation Research- 7 roles
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1. Identify variables and order into taxonomies
2. Develop or refine data collection instruments 3. Understand context-dependent phenomena 4. Patient experiences and behaviors 5. Provider perspectives and behavior 6. Theory development 7. Generation of hypotheses |
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4 values in qualitative research, determine rigor
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credibility (truth)
transferability (applicability) dependability (consistency) confirmability (neutrality) |
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Database definition
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compilation of research evidence resources, primarily lists of peer-reviewed journal articles, designed to organize the large amount of research published every year
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search engine definition
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user interface that allows specific articles to be identified in a database
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national guidelines clearinghouse characteristics
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-database of clinical practice guidelines
-contains CPGs not indexed in medline -has its own search engine, which has limited functionality but allows searching for broad terms |
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physiotherapy evidence database characteristics
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-freely available database and search engine of abstracts for physical therapy specific literature
-covers only intervention-related literature -uses a rating system, 10/10 least bias |
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Hooked on evidence definition
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physical therapy specific database developed by APTA
only available to members |
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Cochrane library of systematic reviews
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-database of systematic reviews conducted by cochrane-approved reviewers
-reviews indexed in PubMed -separate cochrane search engine is available |
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MEDLINE database characteristics
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indexes over 5200 journals published from around the world and across numerous medical and related disciplines
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PubMed characteristics
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-freely available search engine developed by U.S. National Library of Medicine and National Center for Biotechnology information
-nearly all PubMed searches are contained in the MEDLINE database |
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google scholar characteristics
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designed to search internet for journal articles
searches all entries included in PubMed and National Guidelines Clearinghouse |
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Translating research into practice
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-powerful search engine designed to assist medical practitioners in searching numerous databases to find the best available evidence
-TRIP searches PubMed/MEDLINE, National Guidelines Clearinghouse, and more than 20 other prescreened databases |
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Key words definition
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-important words from your searchable clinical question and/or synonyms of those words
-ideally, an article that has your key words in the title and abstract will be relevant to your searchable clinical question |
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MeSH terms characterstics
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-Medical Subject Headings (MeSH)
-within pubmed you can enter key words from your question into a MeSH database to determine the best MeSH term for that topic -MeSH can be limited, in which case key words are better to use |
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Next step after identifying most important terms when using a database
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combining terms using OR and AND
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Boolean operator OR fxn
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Using OR retrieves a list of all the articles that have either the term
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Boolean operator AND fxn
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used when you only want articles hat contain both (or more than two) terms
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limits fxn
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can be used to limit the results of a search to the types of articles in which you are interested
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credibility definition
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Confidence in findings based on research design, informants, & context
Adequate representation, description, or interpretation of experience |
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transferability definition
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-Goodness of fit of the findings to contexts outside those studied
-Dependent on degree of similarity of sending & receiving contexts -Burden of proof is responsibility of person wishing to transfer findings, not original investigator |
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dependability definition
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-Trackable variability so that variability can be traced to identified sources
-Taking into account factors of instability and factors of phenomenon or design -There is no credibility without dependability |
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confirmability definition
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Neutrality of the data so that findings are a function of the informants and condition, not bias of the researcher
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truth value rationalistic and naturalistic paradigms
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rationalistic- internal validity
naturalistic- credibility |
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applicability rationalistic and naturalistic paradigms
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rationalistic- external validity
naturalistic- transferability |
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consistency rationalistic and naturalistic paradigms
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rationalistic- reliability
naturalistic- dependability |
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neutrality rationalistic and naturalistic paradigms
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rationalistic- objectivity
naturalistic- confirmability |