Finding the Evidence: Search Basics Ilo-KatrynMaimets email@example.com 416-736-2100 x33927 Steacie Library room 102K
Evidence-Based Health Care “The integration of best research evidence with clinical expertise and patient values to facilitate clinical decision making” (Sackett et al., 2000)
AGENDA • Sources of Information – Library website • Databases & More • Study Design – Hierarchy of Evidence • Conducting a Literature Search • Search tips and Boolean Logic • Keyword searching • Subject heading searching • Steps in Evidence-based practice • Levels of Pre-Appraised Evidence
A. Identify Sources of Information • Select Sources that will most likely answer the question: • If the information is most likely found in Medical or Nursing research journals then start your search in a database that indexes that kind of research: • Cinahl (Nursing and Allied Health) • Medline(OVID) and PubMed • SCOPUS (interdisciplinary - indexes part of Embase) • Web of Science (very interdisciplinary) • Note that sometimes relevant research is indexed in: • PsychINFO (psychology) • Eric (education)
A. Sources of Nursing Information in the York Library Website: www.library.yorku.ca
Research Guides • Use the Research Guides to locate: • General/Getting Started: Dictionaries, Encyclopaedias and e-books • Articles/Finding articles: • Links to Databases • Systematic Reviews and Evidence-based Practice Resources • Advanced/Advanced Research: • Association and organizations • Webguides and other resources • Other Related Research Guides and Resources
Nursing Research Guide http://researchguides.library.yorku.ca/nursing
B. Study Design: The hierarchy of Evidence
Study Designs: descriptive and analytic Centre for Evidence Based Medicine, University of Oxford http://www.cebm.net/index.aspx?o=1039
Hierarchy of Evidence: Study Designhttp://guides.mclibrary.duke.edu/content.php?pid=274373&sid=2289252Connie Schardt, Medical Centre Library, Duke University Cohort Studies Meta Analyses Secondary studies which review original research Systematic Reviews Randomized Controlled Trials Experimental designs Case Control Studies Observational reports and studies Case reports / case series
Case Reports • Reports of observations of diseases, adverse reactions or unexpected events • E.g. observations in the 1980s of a rare cancer combined with pneumonia led to the discovery of HIV-AIDS • However, there are no controls and so there is no statistical validity, and you cannot draw conclusions or make statistical comparisons.
Case Control Studies • These are used to examine Harm questions • Begin with an outcome or issue • Look backwards in time to identify a possible exposure, or risk factor • E.g. observations of lung cancer incidence in the 1950s led to an examination of patient records that uncovered links to cigarette smoking Peto R. Darby S. Deo H. Silcocks P. Whitley E. Doll R. (2000) Smoking, smoking cessation, and lung cancer in the UK since 1950: combination of national statistics with two case-control studies. BMJ. 321(7257):323-9.
Case Control Studies • Are quick, inexpensive, convenient and ethical because the patient already has the condition. • However, evidence is based on recall which may be biased, or on past records which may not be complete because they were created before knowing what the questions were. • There may be confounders that are common to both groups • It is difficult to choose appropriate controls.
Cohort studies • Involve 2 or more populations: • Exposed: having a specific condition or receiving a particular treatment over time • Non-Exposed: group that has not been affected by the condition or treatment being studied • Follow the populations forward in time – sometimes for many years to determine the effect of the exposure. • E.g. long-term effectiveness of influenza vaccines in community dwelling elderly people Nichol KL, Nordin JD, Nelson DB, Mullooly JP, & HakE. (2007). Effectiveness of influenza vaccine in the community-dwelling elderly. New England Journal of Medicine, 357(14):1373-1381.
Cohort studies • Observations are of people in their natural settings • Evidence is strengthened by natural time sequence – exposure occurs before the outcome • Ethical in that patients self-select (this may also be a source of bias) • Possible confounders • Long follow-up – often many years even decades.
Randomized Controlled Trials • True experimental design that introduces a therapeutic randomized/control-placebo intervention • Follows subjects forward in time to determine the effects of interventions • Randomization is key and involves randomly assigning individuals to groups • Less prone to bias, best for establishing efficacy • May present ethical dilemmas • Is very expensive and time-consuming Müller O, Traoré C, Kouyaté B, Yé Y, Frey C, Coulibaly B, et al. (2006). Effects of insecticide-treated bednets during early infancy in an African area of intense malaria transmission: A randomized controlled trial. Bulletin of the World Health Organization, 84(2):120-126.
Systematic Reviews • Secondary research that: • Focusses on a clinical topic • Involves a thorough review of the literature, published and unpublished • Studies are subject to detailed scrutiny of their quality for inclusion • Summarizes data for drawing conclusions that inform practice. Pittler MH, Guo R, Ernst E. Hawthorn extract for treating chronic heart failure. Cochrane Database of Systematic Reviews 2008, Issue 1. Art. No.: CD005312.
Meta Analysis • Mathematically/statistically pools the data from individual studies • Sources of data can be the articles included in a systematic review or from otherwise selected primary studies, both peer-reviewed and grey literature • Present results as if it were from a large study Bahekar AA, Singh S, Saha S, Molnar J, Arora R. (2007). The prevalence and incidence of coronary heart disease is significantly increased in periodontitis: A meta-analysis. American Heart Journal, 154(5):830-7.
Systematic Review/Meta Analysis • Exhaustively reviews the current literature • Articles are critically evaluated for inclusion • Pooled data allows validation of findings in small studies • Publication bias may be a problem as negative results are less often published than positive results • Conducting them is very time consuming and so also expensive • Data parameters and collection methods are not always the same from study to study, and so studies cannot be easily combined.
Study Design: Hierarchy of Evidencehttp://guides.mclibrary.duke.edu/content.php?pid=274373&sid=2289252Connie Schardt, Medical Centre Library, Duke University Cohort Studies Meta Analyses Secondary studies which review original research Systematic Reviews Randomized Controlled Trials Experimental designs Case Control Studies Observational reports and studies Case reports / case series
Qualitative vs. Quantitative • EBP started as part of medicine to determine best practices in quantitatively measurable procedures, effects, etc. However, in nursing, many questions are asked that cannot be answered by quantitative data. • For example: what is the lived experience of women identified as carriers of the BRCA gene? • In most EBP rating scales, qualitative evidence is deemed to be low on the scale for quality and validity
Quantitative Study Designs based on question type DiCenzo, Guyatt, Ciliska, 2005, pg 28 • Healthcare interventions: treatment, prevention, therapy • Harm: causation or etiology • Prognosis: future course of the condition • Diagnosis/assessment • Economics: economic efficiency of healthcare programs or interventions
Qualitative Study Designs: DiCenzo, Guyatt, Ciliska, 2005, pg 32 • Case studies: involves studying a number of related cases in depth to inquire into an observed phenomenon. The belief is that understanding them will lead to a deeper understanding of a larger collection of cases. • Ethnography: involves studying people within a culture in an intensive, ongoing, participatory way. The researcher is immersed in the culture for the duration of the study.
Qualitative Study Designs: DiCenzo, Guyatt, Ciliska, 2005, pg 32 • Grounded Theory: involves discovering meanings that people assign to people and objects or situations that they interact with. The purpose is to develop a theory to account for individual differences. Interviews and observation are used to collect data • Phenomenology: examines the daily lived experience of people. Data are collected through in-depth interviews.
Qualitative Systematic Reviews: • Do not use statistical methods to combine findings and data • Adhere to a systematic process for retrieving sources, selecting sources, and critiquing sources • Their purpose is to synthesize the findings from multiple studies, and this process is called Meta-synthesis. Levine and Feldman, 2006, pg 178
Qualitative Meta-Syntheses: • Uses data from different qualitative studies that are linked because they are about the same or a related by topic. The methodologies used can be different. • Is neither an integrated review nor a secondary analysis of primary data. • Rather it is an analysis of the findings of these studies
Integrative Reviews: • Are similar to qualitative systematic reviews, however, they use broader, often less rigorous methods to systematically combine the results of a body of studies. Stevens, 2002, pg 530 • “The integrative review method is an approach that allows for the inclusion of diverse methodologies (i.e. experimental and non-experimental research) and has the potential to play a greater role in evidence-based practice for nursing” Whittemore, 2005, pg 547 http://users.phhp.ufl.edu/rbauer/ebpp/whittemore_knafl_05.pdf
Realist Syntheses: • Focus is on understanding and analyzing the mechanisms by which an intervention works or fails to work • Provides an explanation rather than a judgement about implementation and success of an intervention • Accounts for not just outcomes but also context of the intervention • By nature, RSs are well suited to complex implementation interventions
Realist Syntheses: • Implementation interventions are by nature complex and multi-faceted. • When developing and implementing an intervention, there is an underlying theory about how it should work. • Deterministic theories cannot always explain or predict implementation outcomes in every context. http://www.ccsr.ac.uk/methods/publications/RMPmethods2.pdf
Narrative Synthesis: • Method to synthesize research in the context of systematic reviews that uses a narrative approach to summarize findings. • Does not exclude numerical analyses and can occur alongside Meta-analyses • Combines heterogeneous studies, and has not (yet) been developed according to consensual structurally and thematically coherent framework to describe a complex body of evidence
What kind of study is this? Good place to start – not exhaustive Health Sciences Library, McMaster University. Tips for Searching for the Evidence [Internet] [cited 2012 1/8/2012]. Available from: http://hsl.mcmaster.ca/education/nursing/ebn/search.htm
C. Conducting a Literature Search a. Search tips and Boolean Logic
The logic of searching - Tips • Booleans, Brackets, Truncation, Quotation marks • These features apply to most but not all Health and Science Databases • If you are not sure, always check the Help Menu to see the syntax for the database you are searching
The logic of searching Use Boolean Logic to put together your search terms: AND OR NOT
Boolean Logic:AND AND: Finds those citations that contain both search terms joined by AND AND is used to find the intersection of different concepts isolation AND depression
Boolean Logic: AND i i i d i d d i i id d i i d d i id Isolation Depression id i i i id i d i d id i i i d d d isolation AND depression
Boolean Logic:ORand brackets: () OR: Finds citations with ANY search terms joined by OR OR is used to join synonyms and related terms of the same concept: isolation OR quarantine read: either isolation OR quarantine OR both N.B. use brackets if you have more than one term for a concept: (isolation OR quarantine)
Boolean Logic: OR i i i q i q q i i q iq i i q iq i iq i iq Isolation Quarantine i iq q i i q i q i i iq i q q q (isolation OR quarantine)
Boolean Logic: NOT NOT: Finds citations that DO NOT contain these search terms (check the database syntax to see what is used for the exclusion term e.g. some use BUTNOT) NOT is used to exclude a set of results when you find that you are too many false hits on an unrelated topic (Isolation OR quarantine) NOT seclusion
Boolean Logic: NOT i q q i i q q i iq iq i Quarantine iq Isolation i i q q q i q i i i q iqs iq q NOT Seclusion q i sq i q is is sq (isolation OR quarantine) s s s s s Seclusion s s
Truncation and Wildcard • Truncation symbol: * To use truncation, enter the root of a search term and replace the endings with an *. • Example: typing nurs* will find the words nursing, nurse, or nurses as well as nursery, nurseries etc. • Wildcard symbol: ? To use the wildcard, replace each unknown character with a ?. • For example, type wom?n to find all citations containing woman or women. • NB: the wildcard replaces a single character, so behavio?r will only retrieve behaviour and not behavior because the number of characters do not match • Note that different databases may have different symbols and techniques for Wildcard and Truncation
Phrase searching • MEDLINE and CINAHL- the search: well being will find well and being anywhere in the text fields In Medline, to find the phrasewell being search: well being Searching well adjN being will find articles where well and being are within N words from each other in any order In CINAHL, to find the exact phrase well being search: ”well being” Different databases may have additional operators such as Adjacency Operators – check the Help Files for these
Boolean Logic: Test Example Which phrases would you find with the search: Isolat* AND depress* • Isolation is associated with falls • Quarantine is required for SARS • Isolation can trigger depression • Isolation is associated with adverse effects • Is depression an outcome of isolation?
Test Example Which article(s) would you find with the search Isolat* OR quarantin* • Patients with MRSA are isolated • In vitro protein isolation • Quarantine prevents the spread of rabies • DNA purification is a complex process • Both isolation and quarantine can have detrimental effects on emotional well-being
Use Brackets to Group Together Search Terms Which phrases would you find with the search: (isolat* OR quarantin*) AND (depress*) NOT seclu* • Isolation can lead to depression • Quarantining patients with MRIs can trigger depressive symptoms • Rabies was isolated from quarantined raccoons • Does severe depression warrant seclusion?
Conducting a Literature Search • Identify a problem for investigation • Develop a structured research question • Identify key concepts in the question • Develop a Keyword search strategy by identifying searchable terms: • Find keywords: synonyms & related terms for each concept • Combine with Boolean Logic • Subject Heading Search – using MeSH or equivalent • Select sources of evidence e.g. databases • Test search with vocabulary suitable to the database • Modify your search strategy if necessary • Run the search • Retrieve articles and appraise them for suitability
Define the Problem • Determine a Problem that you want to investigate: • Example Problem: Current practice requires that patients with multidrug-resistant infections be place in isolation. However, isolation has recently been associated with adverse effects on patients’ mental well-being.
Ask a Structured Question • Develop a Question that willfocus the information you will be gathering • Example Structured Question: Does patient isolation increase the incidence of depression?
Identify Key Concepts • What are the main concepts in your question? Does patient isolation increase the incidence of depression? Concept 1: patient Concept 2: isolation Concept 3: depression