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Search Skills in Medical Sciences

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Presentation on theme: "Search Skills in Medical Sciences"— Presentation transcript:

1 Search Skills in Medical Sciences
Roya Kelishadi,MD September 2010

2 Objectives: Attendees will Identify good references
Perform a MEDLINE search effectively Find full text journal articles Find info in online textbooks Find online health stats

3 Find the References What are the best?

4 Levels of References Primary: Peer Reviewed
Secondary: Not peer-reviewed Primary When someone says Primary Literature, they usually mean something that is peer reviewed, like a journal article published in a peer reviewed journal or a textbook from a highly respected author who quotes from and cites peer reviewed articles. The secondary level of references or literature refers to things like newspaper articles, authoritative web sites, and such that are usually opinions or reports of occurrences, news, surveys, and such. Also included in secondary sites are databases like the ones at the CDC which are statistics collected from state and local agencies. Secondary

5 Levels of Peer Reviewed Information
Primary: original research Secondary: review articles Tertiary: textbooks, summaries Primary Information Source: Articles in scientific journals that report the findings from research studies and experiments are considered "primary" information sources, because they are "first hand" accounts of the actual research and the results, i.e. the original scientific evidence. Papers about original empirical research must conform to acceptable scientific standards for conducting and reporting such research, and must pass peer-review to be published as articles in a scientific journal Secondary Information Source: The various original scientific studies described above generate a wealth of "primary evidence" that periodically needs to be gathered, organized, and assessed by the clinical and scientific communities to give us a sense of the current "state of the science" on a given topic. These types of research "Review" articles are considered a secondary source because they are "second-hand" accounts which integrate the scientific evidence from a number of original research studies. However, such scientific "Review" articles must also conform to scientifically acceptable methodologic standards for gathering, synthesizing, and reporting the available evidence, and also must be peer-reviewed before being published in a reputable scientific journal. Tertiary Information Sources: Textbooks offer an example of a usually reliable source of information, that may or may not be peer-reviewed. The more accurate and reliable textbooks will contain information that is drawn only from the evidence from primary and secondary source articles that have been published in the peer-reviewed scientific literature, and that conform to scientific standards for summarizing and interpreting that information.  For instance, the author(s) of an accurate and reliable textbook will appropriately and objectively summarize all information available on a topic, and not just "pick and choose" certain evidence or interpret the selected evidence in a biased manner.  In accredited institutions, textbooks are reviewed and approved by the faculty of the institution, which provides another level of "peer-review" of the information in the textbook. Textbooks in wide use by a number of accredited institutions may give a further indication of the extent to which educators, clinicians, and scientists consider the book a credible and legitimate source of accurate and complete information Primary Secondary Tertiary

6 Primary Peer Reviewed Literature
Primary Source Evidence: The second table (Slide 6) titled "Continuum of Study Designs and their Causal Inference" demonstrates the hierarchy of the different types of research studies. This hierarchy is based on the ability of the research study design to satisfy the "Criteria for Causality" (some of which were identified in the previous slide). The research examples at the bottom of the table (e.g. case studies) are good for beginning the process of developing cause-and-effect research hypotheses, but such studies can only provide very weak evidence since they don't meet many of the Criteria for establishing Causality. For example, in testing a new angina drug, viagra, there was this interesting side effect. Moving from the bottom to the top of the pyramid, the rigor of the research studies is increased, more of the causal criteria are met, and a stronger case may be made for drawing conclusions (inferences) about cause-and-effect. At the top of the triangle is the experimental randomized controlled trial (RCT), which is the strongest study design for meeting the causal criteria, and therefore is the "gold standard" of scientific evidence. 

7 Secondary Sources Secondary Source Summaries of Evidence:
The "primary evidence" from the research studies described above is periodically "Reviewed" by gathering all of the evidence available on a given topic, and comparing and contrasting the various research studies and the results from those studies. Review articles follow acceptable scientific methods which again make use of the common-sense "Criteria for Causality" to compare and contrast the strength of the different studies for supporting (or refuting) a hypothesized cause-and-effect relationship. Generally, Review articles fall into one of 3 broad categories in order of increasing scientific rigor: the narrative review, the systematic review, and meta-analyses, which are briefly described below. Narrative Reviews are essentially "essays" wherein the researcher/author focuses on a particular clinical topic, and presents in their opinion what they feel are some of the highlights worth noting from the scientific literature they review. Narrative Reviews are the weakest of the "Secondary Source" research literature, since the methods and the reporting are somewhat subjective, and therefore may be more prone to bias. Articles that report original empirical research studies (described as "Primary Source" evidence above) typically also contain good "narrative overviews" of the "existing evidence" as an introduction and background to the article, to explain and justify why the original research study was conducted. Systematic Reviews are conducted according to scientific methodologies that are explicit, explicitly stated, and reproducible. For instance, the methods section of a systematic review will describe the literature search in enough detail (e.g. what databases were searched, for what years, search terms employed), that the search strategy could be replicated by another researcher and produce essentially the same yield of literature. The "primary evidence" articles are then systematically and explicitly compared and contrasted along a number of important dimensions of research designs that reflect the "Criteria for Causality", which makes for a stronger and more useful "review of the resulting evidence" than do simple narrative reviews. This "attention to detail" in conducting and reporting the systematic review, helps the readers of the review article (i.e. the clinical and scientific communities) to determine how strong the accumulated evidence appears to be, without relying solely on the opinion of the author. Meta-Analyses take the systematic review to the highest and most rigorous level of integrating "primary evidence" research, by statistically synthesizing the quantitative results across similar studies. Essentially, meta-analyses pool the data and results from a number of original research studies, with the intent of producing a more precise summary of the existing evidence for (or against) a cause-and-effect relationship.  For example, a meta-analysis may collect results from a number of epidemiologic studies, and statistically combine the data to produce a more precise overall "risk estimate" of the relationship between the causative risk factor and the effect (the disease).

8 The Top 10 Medical Resources

9 Centers for Disease Control and Prevention (CDC) :
Description The CDC is the site to visit if you are looking for information on chronic diseases,injuries and disabilities, or guidelines on their prevention. In addition to these sources, the CDC has valuable data on travellers’ health, plus full-text access to the Morbidity and Mortality Weekly Report (MMWR). Cost Free Analysis The stated aim of the CDC is to ‘promote health and quality of life by preventing and controlling disease, injury and disability. In addressing this broad agenda the CDC has developed numerous information resources of use and interest to all health professionals. Fortunately, many of the resources held at CDC can be accessed through one sophisticated search tool, known as CDC WONDER :

10 CDC WONDER CDC WONDER provides query access to about 40 text and numerical databases. For example, When you select the mortality data set, to retrieve data on the causes of death, you can define your search parameters to include a particular state, race, gender or age. Text databases such as the Prevention Guidelines and the MMWR can be searched by keyword. For information about travellers’ health, CDC provide a hypertext map of the world. By pointing and clicking your mouse on a particular country you can identify its current vaccine requirements, details of any prevalent diseases, plus general health and travel advice. This type of information is updated on a regular basis to take account of recently reported disease outbreaks.

11 Internet Mental Health
Description A one-stop source for authoritative information on mental illness. Cost Free Analysis Internet Mental Health describes itself as a ‘free encyclopedia of mental health’. Detailed here is information on the most prevalent mental disorders, supplemented with the most common psychiatric medications. For every mental disorder discussed, visitors to the site can find a description of the illness, read a synthesis of recent research into its diagnosis, treatment and cause, and be directed to information booklets compiled by professional organizations and support groups. Drug information at this site includes details on adverse effects, contraindications and dosages. The site also enables you to perform an online diagnosis of a number of disorders including anxiety, eating, mood, personality and those related to substance abuse. Diagnosis is based on the results of a questionnaire you complete while online. Although only a qualified professional can accurately diagnose a mental disorder its use as a teaching aid may be considerable.


13 National Institutes of Health (NIH):
Description Recognised as one of the world’s foremost biomedical research centres, the National Institutes of Health provide a range of invaluable sources of information for health professionals. Cost Free Analysis The mission of the NIH is to ‘uncover new knowledge that will lead to better health for everyone’. It works towards this mission by conducting its own research and supporting the research of scientists throughout the world [Its budget for 1998 was $13.6 billion]. The Web site has links to many health information resources that come under the NIH umbrella. Some of the key links include: • The Consensus Development Program. The Consensus Statements and the Technology Assessment Statements that are authored under this program are authoritative guides to current medical issues. Scanning the titles of some of the most recent Statements – ‘Effective medical treatment of opiate addiction’ and ‘Acupuncture’ – demonstrates the commitment of the NIH to focus on clinical issues. • CancerNet. Developed by the National Cancer Institute (NCI), CancerNet provides fact sheets on topics such as cancer detection, prevention and therapy. It is also possible to perform a literature search on the CancerNet database to identify references to published journal articles, conference proceedings, government reports and monographs that relate to cancer.

14 OncoLink:
Description Detailed and authoritative information on all aspects of cancer. Cost Free Analysis This site is the only one within this list that is disease specific. Its inclusion, however, reflects the quality of the information and the ease with which cancer-related questions can be answered. A clear and simple front menu allows you to approach the resources at OncoLink by 10 main categories, including disease, medical specialty (chemotherapy, surgical oncology etc.) and the causes of cancer. For cancer patients and their families the ‘Psychological Support Menu’ provides links to documents that discuss how one can cope with cancer, as well as specific issues such as ‘Coping with grief and loss’. In contrast, physicians undertaking research on cancer can link to the ‘Clinical Trials’ section. Here, all trials currently being conducted by the National Cancer Institute and the University of Pennsylvania are cited and discussed. If the subject you are searching for does not lend itself to this menu approach, the OncoLink search engine can be used. As this uses AltaVista technology searching is both familiar and very fast. A search for +malignant +melanoma +sun, for example, produces a ranked list of> 55 relevant documents. Perhaps the most remarkable aspect of the OncoLink Web site is that, despite the mass of information held here, it is very easy to find what you are looking for.

15 PubMed – MEDLINE on the Web www. Description PubMed, developed by the National Library of Medicine, provides a free World Wide Web interface to MEDLINE, the world’s premier biomedical database. Dating from 1966, the MEDLINE database currently contains just more than 10 million bibliographic citations drawn from around 5000 biomedical journals. Cost Free Analysis Free Internet access to MEDLINE is a relatively new service but one which an increasing number of Web sites now offer. An annotated list of free MEDLINE sites is available at: SPages/ medline.asp Though all these services have unique and useful characteristics, it is considered that the PubMed MEDLINE to be the best version currently available. The strengths of this service are: • Currency. By incorporating data from the Pre-MEDLINE file, citations appear in the database far more quickly than in other versions of MEDLINE. Some measure of the currency of PubMed can be gauged by the observations showing that articles published in journals such as JAMA and the New England Journal of Medicine are indexed – and thus searchable – within one week of publication; articles from the BMJ and Lancet appear within a fortnight of publication.

16 Pubmed(cont.) • Powerful searching. Using pulldown menus it is possible to search specific MEDLINE fields (author name, MeSH term, title word, etc.) and use the Boolean operators (AND, OR and NOT) to combine search terms. PubMed also has a ‘Clinical Query Filter’ that allows you to restrict a search to one of different study categories. Once a search has been run and citations selected, PubMed also gives you the option to find other related articles. • Links to full-text articles. The NLM is currently establishing links with various publishers to enable MEDLINE searchers to link directly to the full text of a given article. (Note: This feature is publisher specific and users may incur a fee to see the full text of an article.) • Dynamic links with related databases. A number of MEDLINE articles have links to related databases, such as the Online Mendelian Inheritance in Man (OMIM) database and the Molecular Modelling Database (MMDB).



19 Reuters Health:
Description A health and medical daily news service keeping health professionals abreast of health stories and scares. Cost [may be charged]. Analysis Covering around 50 news stories per day, Reuters Health News is the most comprehensive medical news service on the Internet. To help health professionals find stories most pertinent to their interests, articles are organised into a number of discrete categories, such as clinical, epidemiology and public health. Alternatively, relevant current and archive stories can be identified using a powerful search interface. All news items cite the original source of the story – typically a research item in a medical journal – and if a story contains a reference to a particular drug, there will be a hypertext link to Reuters Clinical Pharmacology database, where additional information can be found. Although this is a subscription-based service, visitors can access the consumer health stories and a number of items from the medical news section every day, without charge. Searching facilities, however, are restricted to subscribers. Free Alternative The Medical News pages of the Doctor’s Guide to the Internet: and have a reasonably comprehensive news coverage which, if you wish, can be sent to your electronic mailbox on a regular basis. Searching of the news archive is also possible at this site.


21 RxList – the Internet drug index
Description A database of prescription pharmaceuticals. Cost Free Analysis RxList, the ‘Internet drug index’, provides information on prescription drugs. Drug information can be found by either searching the database – by brand or generic name, imprint code or drug category – or by browsing the ‘Top 200’ prescription drugs.

22 RxList (Cont.) When searching by brand, US names as well as ‘foreign’ ones can be searched for. Basic prescribing data is supplemented with 300 RxList monographs. These detailed reports describe key features such as contraindications, adverse effects and drug interactions.


24 TRIP – Turning Research into Practice www. gwent. nhs. gov
TRIP – Turning Research into Practice trip/test-search.html Description A searchable index to the premier evidence-based medicine (EBM) resources. Cost Free Analysis One of the problems facing the clinician who wishes to practice evidence-based medicine (EBM) is the disparate way research findings are disseminated. Although the Cochrane Database ( is the best source for identifying the results of systematic reviews, other sources, such as clinical practice guidelines and briefing papers, may also be of interest. Finding this information can, however, be extremely time-consuming. In recognition of this, the Primary Care Clinical Effectiveness Team for Gwent have created the TRIP database, a single searchable index to a range of EBM resources. Sources indexed by TRIP include the Cochrane Database of Systematic Reviews, Canadian Clinical Practice Guidelines Infobase, Database of Abstracts of Reviews of Effectiveness (DARE) and the evidence-based health-care journals Bandolier and Evidence Based Medicine.



27 WebMedLit:
Description WebMedLit provides health professionals with a way of keeping up to date with research published in a number of quality medical journals, including BMJ, JAMA and the NEJM. Cost Free Analysis Describing itself as a ‘medical headlines service’, WebMedLit scans the Web every day for updates to the medical titles it is currently tracking. For example, the BMJ, published on a Friday, is picked up by this service and is indexed and searchable by Saturday morning. Articles remain in the WebMed-Lit database for around 6 weeks. After this time they should be retrievable at the PubMed MEDLINE site. What differentiates WebMedLit from the countless other Web sites providing links to medical journals is its citation database. This gives users the opportunity to search the contents of these top medical journals from one source, and the functionality to link directly back to the article (or abstract) at the individual journal’s Web site. As an alternative to searching the WebMedLit database, the latest medical literature can be viewed by subject. Ten general subjects have been defined, including AIDS, cardiology, and cancer.



30 World Health Organization
Description Details of WHO programmes (Global Programme for Aids, Global Programme for Vaccine and Immunisation, etc.); database of WHO publications; statistical databases; Weekly Epidemiological Report; press releases and newsletters. Cost Free Analysis In recognition of the importance of the Internet, the WHO has made the Weekly Epidemiological Report available via the World Wide Web. This electronic journal provides health professionals with a means of obtaining rapid and accurate epidemiological information,along with details of new disease outbreaks. To identify subject-specific WHO resolutions, guidelines and journal articles, the WHO Management Information (WHOMIS) can be searched. The WHO also provides a statistical service (WHOSIS) giving Internet users access to a variety of data sources, such as WHO Global Health for All Indicators Database and the Global Programme for Vaccines and Immunization Incidence data.



33 What is MEDLINE? >5,000 biomedical peer reviewed journals
Old Index Medicus database National Library of Medicine (NLM) >12 million citations Back to mid 1960s

34 Where is MEDLINE? Pubmed (NLM) OVID MD Consult etc Links to
Full text journal articles Books EBM databases Yes, it is true. MEDLINE is all over the place. Selecting the search engine to go with the search topic is an important decision. OVID provides a powerful search engine, allowing for quick access to MeSH, command searching, cross-file searching with EBM databases, and links to MEDLINE in context to references and other full-text articles within the OVID selection of 82 electronic journals. MD Consult provides one-stop shopping with reference and text books, current articles patients are reading, web resources, and over 40 electronic journals. (The search engine for MD Consult is not as good as OVID’s search engine.) Pubmed includes Biomed Central journals and a feature called Linkout. Once activated at FSU, approximately 1,000 electronic journal titles will be linked to specific references. Science Direct links MEDLINE references to a large group of FSU-subscribed e-journals published by Elsevier. Cambridge Scientific is another FSU-subscribed vendor but I can’t recommend it for MEDLINE searching. Medscape is a very popular Internet site with a broad range of free literature, although much of the full-text information is not peer reviewed. I could go on. I won’t!

35 MEDLINE Fields Author Title Date Type of publication
Journal, Volume, Issue Page numbers Abstract Institution MeSH Headings A lot of cataloging numbers etc

36 What’s a MeSH Heading? "Medical Subject Headings"
vocabulary terms from subject analysis of literature indexing journal articles for Index Medicus® and MEDLINE cataloging books and audiovisuals controlled vocabulary arranged in a hierarchical MeSH Tree Structures updated regularly

37 Examples of MeSH Headings
Pubmed MeSH Database

38 PubMed MEDLINE Entering PubMed
Type search terms Tutorial Save searches in your custom ‘cubby.’

39 PubMed MEDLINE Preliminary Results
Large number of hits. Click on ‘Details’ to show how PubMed translated the search. (You can modify the search by typing in the text box.)

40 Boolean Operators AND OR NOT Parenthesis * quotes
“medic* errors” AND “quality improvement” NOT (ambulatory OR “nursing home”)

41 PubMed MEDLINE Limit Results
Click on ‘Limits’ Limits added in this search: - Clinical Trials - Adults over 19 years - Human subjects - Indexed in the last 2 years.

42 PubMed MEDLINE Refined Results
Number of hits is still quite large. (361 from previous 92,441) Add ‘AND diet therapy’ to the search terms. (AND, OR, & NOT operators must be in all capitals.)

43 PubMed MEDLINE Use History #2 AND #3
Combining Searches Use History #2 AND #3 Click on number of hits to see results

44 PubMed MEDLINE Getting the articles
Select ‘Abstract’ view and click on ‘Display’ Click on FSU icon to link to full text.

45 4 1 3 2

46 Searching Ovid Pick database PREMEDLINE and MEDLINE, 1966-present

47 OVID Search Screen Author Title Journal Search fields Tools Combine

48 Tricks Find one good article Look at MeSH headings
Find similar articles Use Related Articles in PubMed Search same MeSH terms

49 Too Many Hits: Increase Specificity
Use more specific terms in free text search Use mesh search rather than text word search Combine searches Use more specific mesh headings Add terms (using AND) Limit language of article human or animal subjects publication types (e.g. randomized controlled trials, reviews, etc.) Type of the study year of publication Age group etc When you get too many hits you will need to Increase Specificity by narrowing your question using more specific terms in Free Text search using a Subject search rather than Textword search using more specific Subject headings selecting specific subheadings with Subject MeSH headings adding in terms (using AND) to represent other aspects of the question limiting to language of article, to human or animal subjects, to publication types (e.g. randomised controlled trials, reviews, etc.), to country or year of publication.

50 Too Few Hits Increase Sensitivity
Find more search terms from good articles Try different combinations of terms Use truncation (*) or wildcard (?) in Text word OR Subject Use OR to add and combine terms Use NEAR to retrieve same sentence items, either order Use combination of Textword and Subject searches Select All Subheadings with Subject MeSh terms Search further back in time When you find nothing or just a few articles you need to Increase sensitivity by: broadening your question! finding more search terms from relevant records trying different cobinations of terms using truncation (* or $) or wildcard (?) in Free Text/Textword OR Thesaurus/Subject adding in and combining terms of related meaning using OR using NEAR to retrieve items in the same sentence in either order using a combination of Free Text/Textword and Thesaurus/Subject searches using explosion feature of Thesaurus searches selecting All Subheadings with Thesaurus/Subject MeSh terms searching further back in time

51 Find Good Articles Recent Applicable Relevant Good research criteria
Not just the first full text articles you find

52 Visual Representation
OVID, PubMed Yes No eJournals List Follow Link Use Volume, Issue, Page# Yes No

53 Visual Representation
OVID, PubMed Web LUIS Follow Link Use Volume, Issue, Page# Yes No No eJournals List No

54 Recommendation Save PDF in My Documents Create library of articles
Add link in Favorites

55 Finding Health Statistics

56 Types of Health Statistics Questions
Fact lookups Research Presentations Social and Policy indicators etc For Fact Lookups, you need to find a table with the answers you need. One should understand the source of the information like the Census bureau or CDC while relating it to the definitions and knowing its limits. Look for a prepared table of digested data in published reports. When doing research or a presentation you need information to form the bases of comparisons. In this case you will need to consider which population you are talking about and what question you are answering. talking about and what question you are answering. You may need both journal articles and the original data. For Health and social policy, you need statistical indicators of progress. Uses can include drafting policies or legistation, monitoring success of health care and measuring the impact on society. Health indicator can include Quality of life indicators Public health progress Quality of care Evaluation of efforts You will need literature that summarize results and table that focus on key points.

57 Internet Portals of Health Stats
Lists of links that provide starting points for browsing or searching Keyword search in portal vs Google General idea what you want The Related Health Services Research Web Sites The NCHS portal: For links to portals, go to Related Health Services Research web sites. The Data Sets and Health Statistics sections are particularly relevant. Go to the NCHS site and explore the variety of statistical resources available. What parts of this site are useful for fact lookup, research and indicators?

58 Other Statistical Web Sites
CDC Data and Statistics FedStats Home Page Compare these two U Michigan’s Statistical Resources on the WEB – HEALTH What type of stats

59 Lexis-Nexis Statistical Universe
Subscription resource Searches stat data Subject List Limit search Reports or tables Let’s try it out. Notice you can limit by type of data We can look for reports about tobacco regulations

60 MMWR Morbidity – illness Mortality – death
Disease Trends Tables - searchable The morbidity and mortality weekly report is based on data collected by government agencies. Mortality data is based on death certificates at the National Vital Statistics System. Morbidity data is based on surveys and reports of outbreaks that funnel into the CDC. Only reportable diseases are close to accurate. Wellness data is not available because it is not collected. In the NCSR you can find the whole report on deaths in some year.

61 Health Care Data Healthcare Cost and Utilization Project HCUPnet
Hospital discharges Ambulatory service Costs Amount of care By diagnosis and procedure Surveys of hosp, physicians, nursing homes See if you can find the median cost, length of stay and hospital death rate associated with hosp treatment of acute myocardial infarction.

62 Health Consequences Costs to society, individuals Cost from care
Costs of illness Impact on infrastructure Center for Medicare and Medicaid Services (formerly HCFA) site has all this information

63 State and International Data - Where Florida Health Data Resides DOH Epidemiology KFF State Health Facts Online United Nations Statistics Division World Health Organization Research Tools

64 Create or Open Library Create new Open Save in My Documents File Menu
Name it Pick a folder Open Should pop up Save in My Documents

65 How to Populate the Library
Type in references Connect to Pubmed or other database and capture Search Pubmed or other DB and save results then import In WOS or OVID, search and export directly to Endnote Endnote Library of References

66 How to Type in Citation In Endnote Pick reference type Type in fields
References Menu Select New… Pick reference type Type in fields Close the window

67 How to Capture References
Endnote Tools Menu Choose Connect… Pick a source MEDLINE -> Pubmed at NLM If OVID, ignore userID and PW, hit OK

68 Perform Search If article known Use Author and Title Perform Search
Pick article Copy Reference to... Your Library

69 Cite While You Write Cursor on spot In Endnotes Select reference
With Library open Select reference Tools Menu Cite While You Write Insert Selected Citation Citation and reference appear Endnote Toolbar in Word


71 CONCLUSION The only way to fully appreciate and exploit the range of resources described in this session is to visit these sites and explore. In particular, it is important to pay special attention to the ‘What’s New’ links. Although at times these may simply serve to distract you from your original objective, on other occasions they will bring to your attention new and useful resources which otherwise would have remained undiscovered. As you trawl the Internet you will undoubtedly discover numerous other sites of interest and effectively compile your own ‘top ten resources’.

72 Questions ? Comments?! Thank you for your attention!

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