Focused Searches

Background

The National Library of Medicine (NLM) in the USA is the provider of PubMed, a biomedical database comprising both MEDLINE and non-MEDLINE records. The database records are not an exact replica of the original article but rather an indexed and abstracted reflection of it. From the database provider’s perspective there are essentially three steps involved in converting documents, from their originally published format, into discoverable, searchable and retrievable database records. These are,

Step 1: The document is published in a source indexed by NLM for inclusion in PubMed/MEDLINE.
Step 2: The document’s record is created and enters NLM’s editorial and technical processing systems.
tep 3: The document’s record completes all the required processing for its designated status.

The processing of the document’s record is marked by a variety of time stamps, which as database fields, are indicated in the database record of the original document and hence are also searchable fields. Such instances include; the Year of Publication (YR), the Electronic Date of Publication (EP), the record’s Create Date (DT) as well as the Entry Date (ED). All these fields are phrase-indexed and are searchable using the format YYYYMMDD. An exception being the Year of Publication (YR) which has the format YYYY for both display and searching purposes.

This Focused Search look at ways in which searches can be limited to general or specific spans of time.

Limiting by a range of complete years:
The easiest way to limit a search to a range of complete years is to use the Year of Publication (YR) field. This field is marked and populated by the indexers as soon as the processing of the original document begins.  The database’s Limits function provides the option for the user to enter the wished for date range. Alternatively, set ranges, i.e. 3 Years, 5 years etc. can also be selected. All the records in PubMed and hence in Ovid MEDLINE have a year of publication. But note this is distinct from the dates connected to the document’s record being processed for inclusion in the database.

Limiting by parts of years:
For searches across parts of years, down to months and even days, Ovid recommends using the Create Date (DT) field. This field marks the date when the document’s record was added to PubMed. As the date reflects the date on which the citation was added to the PubMed database, this is not the date of either the original document’s publication or even its electronic publication in the database. Also as a phrased-indexed field, the Create Date (DT) field lends itself well to truncation. So for example in the expression limit 1 to dt=202401*-202402* will yield results from all of January 2024 to all of February 2024.

Updating search strategies:
Search strategies can be updated using the date range searching methods as described above. However, due to the inherent dynamism within the database’s records management, care must be taken when interpreting the results. An alternative method is to extract the records on, say day x and save them according to their unique identifiers (UI), either as a search in My Workspace or in a external document. Then later, on day y, run the same search and save these results similarly. Use the NOT operator to establish the difference between the results sets for day x and day y. This final result will indicate the number of records additionally found between day x and day y.

Practice Suggestions:

1. How many records are there in Ovid MEDLINE whose publication date is in the 1800s?
2. The journal article entitled On the Cow-Pox was published in 1799. When was this record included in Ovid MEDLINE? When was the record last updated? How could you uniquely identify this record?
3. How could you use date range searching to illustrate the rapid rise of articles in Ovid MEDLINE that discuss the role of ChatGPT in health care?

Reviewers:

Primary: Michael Fanning

Secondary: Charlotte Viken

Review Date: 2024-10-30

Expiry Date: 2025-10-30

Original search produced by:

Ovid Training Team

References:

Ovid / Knowledge Community
How can I limit search results by a date range in Ovid?

OvidGO! / Skills Videos
What are Boolean Operators?
What is an adjacency operator?
What are wildcards?
Truncation of keywords
Phrase searching on Ovid
Subject heading searching

Strategy:

Background

The Challenge: How to find useful information quickly?
Biomedical information repositories such as Ovid MEDLINE and Embase on Ovid, contain tens of millions of database records on past and currently available medical literature. Updated on a regular basis, they are large, diverse, highly structured and relentlessly dynamic general purpose resources. This can present challenges to health care professionals in clinical settings, for whom (a). only a sub-set of the database is relevant to them, and (b). they need to be able to quickly locate references that they can be sure are both clinically relevant and scientifically sound.

The Solution: Tested and trusted search filters
An important category of tried, tested and trusted database search filters are validated search filters. These are search strategies made available by subject matter and information experts who have constructed and developed them using a reference set of data as a ‘gold standard’. The resulting search filters are then tested against a test set of references in order to assess their effectiveness in terms of targeted and reliable information retrieval. Where they consistently exceed a certain threshold they are deemed ‘validated’. Although such search filters, as is here the case, may only be comprised of 4-6 search expression lines, the fact of their validation accords them a preferred status in terms of being an information retrieval option. In short, validated search filters are high quality, reliable ‘knowledge assists’ that help both clinicians and those that advise them on information retrieval matters, e.g. librarians and information specialists, to find useful information quickly.

The Source: Clinical Queries from McMaster University in Canada
As used here by Focused Searches, the phrase ‘clinical queries’ refers to database search filters that have been developed by the Health Information Research Unit (HIRU), based at McMaster University in Canada. Made available as part of their Hedges Project, the clinical query validated search filters cover dedicated ‘purpose categories’ surrounding human health disorders. The purpose categories are causation (etiology), course (prognosis), diagnosis, treatment and therapy, clinical predictions, the economics around human health disorders, studies of quality improvement of health services as well as continuing education of health care professionals. For fuller information on clinical queries, their origins as well as a list of accompanying references, please see  https://hiruweb.mcmaster.ca/hkr/hedges/ .

How to make best use of clinical queries?
This Focused Search presents the clinical query for the HIRU ‘purpose category’ Causation, in three versions. The first version (see #1 in the table below), when used in combination with a human health disorder, has been tuned for maximized sensitivity. This is a broad search that will seek to return the highest proportion of relevant results pertaining to treatments and therapies related to the specified human health disorder. It may also include some less relevant results. By contrast its counterpart (see #2 in the table below) which is tuned for maximized specificity, constitutes a narrow search. It will seek to return the highest possible proportion of least relevant results. Being then such a targeted search, designed to include only the most relevant results, it may in doing so miss some of these otherwise wished for references. A third option (see #3 in the table below) is a search that has been tuned to seek a middle way between the broad and narrow search options, that is, to obtain the best balance between sensitivity and specificity.

Adapted from https://hiruweb.mcmaster.ca/hkr/hedges/medline/

Are these search filters still up to date?
Yes, the clinical query validated search filters are up to date. For further information, please refer to the publications listed in Re: Search Filter - Currency: in the References section below.

Why does the Focus Search display as a list of search lines?
The format of the rendered Focused Search for this clinical query is in two parts. The first part is a single line which contains all the clinical query’s relevant terms and expressions. The second part splits the constituent terms and expressions into their component sub-parts and then lists these line by line. At the bottom of the list of component sub-parts the OR operator is then used to obtain an overall result for all the terms and expressions in combination. This result should always be the same as the very first line. The aim of unpacking the clinical query line by line in this way is to ensure the purpose behind each line is understood as is the Ovid syntax used in the line’s construction.

Ovid Syntax Check

• ‘tw’ stands for ‘text word’, a field in Ovid MEDLINE covering both title (TI) and abstract (AB).
• An .mp or ‘multi-purpose’ search, searches across a set of default fields for the database.
• The character ‘:’ is a wildcard denoting truncation. Ovid now more usually uses ‘$’ or ‘*’.
• Search lines can be connected one after the other using the OR operator. Alternatively the search line can be grouped together using the expression ‘or/2-4’ where ‘or’ refers to the OR operator and  the numbers 2-4 refer to the search lines #2, #3 and #4.

Reviewers:

Primary: Michael Fanning

Secondary: Darlene Ennis

Review Date: 2024-07-15

Expiry Date: 2025-07-15

Original search produced by:

McMaster University

References:

Re: McMaster University, Health Information Research Unit, Hedges Project
For information on clinical queries, as well as a list of accompanying references, please see https://hiruweb.mcmaster.ca/hkr/hedges/

Re: Search Filter - Construction:
Wilczynski NL, Haynes RB. Developing optimal search strategies for detecting clinically sound causation studies in MEDLINE. Proc AMIA Symp. 2003;719-23. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1480286/

Re: Search Filter - Currency:
Navarro-Ruan T, Haynes RB. Preliminary comparison of the performance of the National Library of Medicine's systematic review publication type and the sensitive clinical queries filter for systematic reviews in PubMed. Journal of the Medical Library Association: JMLA. 2022 Jan 1;110(1):43. Full text link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8830395/

Wilczynski NL, McKibbon KA, Walter SD, Garg AX, Haynes RB. MEDLINE clinical queries are robust when searching in recent publishing years. Journal of the American Medical Informatics Association. 2013 Mar 1;20(2):363-8. Full text link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3638187/

OvidGO! / Skills Videos
What is a bibliographic database?
What is the structure of a database?
What is Ovid MEDLINE?
What are Boolean Operators?
What are wildcards?
Subject heading searching

Strategy:

Background

The Challenge: How to find useful information quickly?
Biomedical information repositories such as Ovid MEDLINE and Embase on Ovid, contain tens of millions of database records on past and currently available medical literature. Updated on a regular basis, they are large, diverse, highly structured and relentlessly dynamic general purpose resources. This can present challenges to health care professionals in clinical settings, for whom (a). only a sub-set of the database is relevant to them, and (b). they need to be able to quickly locate references that they can be sure are both clinically relevant and scientifically sound.

The Solution: Tested and trusted search filters
An important category of tried, tested and trusted database search filters are validated search filters. These are search strategies made available by subject matter and information experts who have constructed and developed them using a reference set of data as a ‘gold standard’. The resulting search filters are then tested against a test set of references in order to assess their effectiveness in terms of targeted and reliable information retrieval. Where they consistently exceed a certain threshold they are deemed ‘validated’. Although such search filters, as is here the case, may only be comprised of 4-6 search expression lines, the fact of their validation accords them a preferred status in terms of being an information retrieval option. In short, validated search filters are high quality, reliable ‘knowledge assists’ that help both clinicians and those that advise them on information retrieval matters, e.g. librarians and information specialists, to find useful information quickly.

The Source: Clinical Queries from McMaster University in Canada
As used here by Focused Searches, the phrase ‘clinical queries’ refers to database search filters that have been developed by the Health Information Research Unit (HIRU), based at McMaster University in Canada. Made available as part of their Hedges Project, the clinical query validated search filters cover dedicated ‘purpose categories’ surrounding human health disorders. The purpose categories are causation (etiology), course (prognosis), diagnosis, treatment and therapy, clinical predictions, the economics around human health disorders, studies of quality improvement of health services as well as continuing education of health care professionals. For fuller information on clinical queries, their origins as well as a list of accompanying references, please see  https://hiruweb.mcmaster.ca/hkr/hedges/ .

How to make best use of clinical queries?
This Focused Search presents the clinical query for the HIRU ‘purpose category’ Course (Prognosis), in three versions. The first version (see #1 in the table below), when used in combination with a human health disorder, has been tuned for maximized sensitivity. This is a broad search that will seek to return the highest proportion of relevant results pertaining to treatments and therapies related to the specified human health disorder. It may also include some less relevant results. By contrast its counterpart (see #2 in the table below) which is tuned for maximized specificity, constitutes a narrow search. It will seek to return the highest possible proportion of least relevant results. Being then such a targeted search, designed to include only the most relevant results, it may in doing so miss some of these otherwise wished for references. A third option (see #3 in the table below) is a search that has been tuned to seek a middle way between the broad and narrow search options, that is, to obtain the best balance between sensitivity and specificity.

Adapted from https://hiruweb.mcmaster.ca/hkr/hedges/medline/

Are these search filters still up to date?
Yes, the clinical query validated search filters are up to date. For further information, please refer to the publications listed in Re: Search Filter - Currency: in the References section below.

Why does the Focus Search display as a list of search lines?
The format of the rendered Focused Search for this clinical query is in two parts. The first part is a single line which contains all the clinical query’s relevant terms and expressions. The second part splits the constituent terms and expressions into their component sub-parts and then lists these line by line. At the bottom of the list of component sub-parts the OR operator is then used to obtain an overall result for all the terms and expressions in combination. This result should always be the same as the very first line. The aim of unpacking the clinical query line by line in this way is to ensure the purpose behind each line is understood as is the Ovid syntax used in the line’s construction.

Ovid Syntax Check

• ‘sh’ stands for ‘subject heading’ and searches for an occurrence of the term in this field.
• The prefix ‘exp’ denotes the MeSH has been ‘exploded’, i.e. narrower terms are included.
• ‘tw’ stands for ‘text word’, a field in Ovid MEDLINE covering both title (TI) and abstract (AB).
• An .mp or ‘multi-purpose’ search, searches across a set of default fields for the database.
• The character ‘:’ is a wildcard denoting truncation. Ovid now more usually uses ‘$’ or ‘*’.
• Search lines can be connected one after the other using the OR operator. Alternatively the search line can be grouped together using the expression ‘or/2-4’ where ‘or’ refers to the OR operator and  the numbers 2-4 refer to the search lines #2, #3 and #4.

Reviewers:

Primary: Michael Fanning

Secondary: Darlene Ennis

Review Date: 2024-07-15

Expiry Date: 2025-07-15

Original search produced by:

McMaster University

References:

Re: McMaster University, Health Information Research Unit, Hedges Project
For information on clinical queries, as well as a list of accompanying references, please see https://hiruweb.mcmaster.ca/hkr/hedges/

Re: Search Filter - Construction:
Wilczynski NL, Haynes RB; The Hedges Team. Developing optimal search strategies for detecting clinically sound prognostic studies in MEDLINE. BMC Medicine. 2004;2:23 (5 pages). https://link.springer.com/content/pdf/10.1186/1741-7015-2-23.pdf

Re: Search Filter - Currency:
Navarro-Ruan T, Haynes RB. Preliminary comparison of the performance of the National Library of Medicine's systematic review publication type and the sensitive clinical queries filter for systematic reviews in PubMed. Journal of the Medical Library Association: JMLA. 2022 Jan 1;110(1):43. Full text link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8830395/

Wilczynski NL, McKibbon KA, Walter SD, Garg AX, Haynes RB. MEDLINE clinical queries are robust when searching in recent publishing years. Journal of the American Medical Informatics Association. 2013 Mar 1;20(2):363-8. Full text link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3638187/

OvidGO! / Skills Videos
What is a bibliographic database?
What is the structure of a database?
What is Ovid MEDLINE?
What are Boolean Operators?
What are wildcards?
Subject heading searching

Strategy:

Background

The Challenge: How to find useful information quickly?
Biomedical information repositories such as Ovid MEDLINE and Embase on Ovid, contain tens of millions of database records on past and currently available medical literature. Updated on a regular basis, they are large, diverse, highly structured and relentlessly dynamic general purpose resources. This can present challenges to health care professionals in clinical settings, for whom (a). only a sub-set of the database is relevant to them, and (b). they need to be able to quickly locate references that they can be sure are both clinically relevant and scientifically sound.

The Solution: Tested and trusted search filters
An important category of tried, tested and trusted database search filters are validated search filters. These are search strategies made available by subject matter and information experts who have constructed and developed them using a reference set of data as a ‘gold standard’. The resulting search filters are then tested against a test set of references in order to assess their effectiveness in terms of targeted and reliable information retrieval. Where they consistently exceed a certain threshold they are deemed ‘validated’. Although such search filters, as is here the case, may only be comprised of 4-6 search expression lines, the fact of their validation accords them a preferred status in terms of being an information retrieval option. In short, validated search filters are high quality, reliable ‘knowledge assists’ that help both clinicians and those that advise them on information retrieval matters, e.g. librarians and information specialists, to find useful information quickly.

The Source: Clinical Queries from McMaster University in Canada
As used here by Focused Searches, the phrase ‘clinical queries’ refers to database search filters that have been developed by the Health Information Research Unit (HIRU), based at McMaster University in Canada. Made available as part of their Hedges Project, the clinical query validated search filters cover dedicated ‘purpose categories’ surrounding human health disorders. The purpose categories are causation (etiology), course (prognosis), diagnosis, treatment and therapy, clinical predictions, the economics around human health disorders, studies of quality improvement of health services as well as continuing education of health care professionals. For fuller information on clinical queries, their origins as well as a list of accompanying references, please see  https://hiruweb.mcmaster.ca/hkr/hedges/ .

How to make best use of clinical queries?
This Focused Search presents the clinical query for the HIRU ‘purpose category’ Diagnosis, in three versions. The first version (see #1 in the table below), when used in combination with a human health disorder, has been tuned for maximized sensitivity. This is a broad search that will seek to return the highest proportion of relevant results pertaining to treatments and therapies related to the specified human health disorder. It may also include some less relevant results. By contrast its counterpart (see #2 in the table below) which is tuned for maximized specificity, constitutes a narrow search. It will seek to return the highest possible proportion of least relevant results. Being then such a targeted search, designed to include only the most relevant results, it may in doing so miss some of these otherwise wished for references. A third option (see #3 in the table below) is a search that has been tuned to seek a middle way between the broad and narrow search options, that is, to obtain the best balance between sensitivity and specificity.

Adapted from https://hiruweb.mcmaster.ca/hkr/hedges/medline/

Are these search filters still up to date?
Yes, the clinical query validated search filters are up to date. For further information, please refer to the publications listed in Re: Search Filter - Currency: in the References section below.

Why does the Focus Search display as a list of search lines?
The format of the rendered Focused Search for this clinical query is in two parts. The first part is a single line which contains all the clinical query’s relevant terms and expressions. The second part splits the constituent terms and expressions into their component sub-parts and then lists these line by line. At the bottom of the list of component sub-parts the OR operator is then used to obtain an overall result for all the terms and expressions in combination. This result should always be the same as the very first line. The aim of unpacking the clinical query line by line in this way is to ensure the purpose behind each line is understood as is the Ovid syntax used in the line’s construction.

Ovid Syntax Check

• The expression ‘di.fs’ indicates a search on the MeSH subheading ‘diagnosis’, but as a floating subheading (.fs), i.e. not bound to a specific MeSH term.
• An .mp or ‘multi-purpose’ search, searches across a set of default fields for the database.
• ‘tw’ stands for ‘text word’, a field in Ovid MEDLINE covering both title (TI) and abstract (AB).
• The character ‘:’ is a wildcard denoting truncation. Ovid now more usually uses ‘$’ or ‘*’.
• Search lines can be connected one after the other using the OR operator. Alternatively the search line can be grouped together using the expression ‘or/2-4’ where ‘or’ refers to the OR operator and  the numbers 2-4 refer to the search lines #2, #3 and #4.

Reviewers:

Primary: Michael Fanning

Secondary: Darlene Ennis

Review Date: 2024-07-15

Expiry Date: 2025-07-15

Original search produced by:

McMaster University

References:

Re: McMaster University, Health Information Research Unit, Hedges Project
For information on clinical queries, as well as a list of accompanying references, please see https://hiruweb.mcmaster.ca/hkr/hedges/

Re: Search Filter - Construction:
Haynes RB, Wilczynski NL. Optimal search strategies for retrieving scientifically strong studies of diagnosis from MEDLINE: analytical survey. BMJ. 2004;328:1040-2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC403841/

MF NOTE: What of the 2005 study? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC403841/

Re: Search Filter - Currency:
Navarro-Ruan T, Haynes RB. Preliminary comparison of the performance of the National Library of Medicine's systematic review publication type and the sensitive clinical queries filter for systematic reviews in PubMed. Journal of the Medical Library Association: JMLA. 2022 Jan 1;110(1):43. Full text link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8830395/

Wilczynski NL, McKibbon KA, Walter SD, Garg AX, Haynes RB. MEDLINE clinical queries are robust when searching in recent publishing years. Journal of the American Medical Informatics Association. 2013 Mar 1;20(2):363-8. Full text link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3638187/

OvidGO! / Skills Videos
What is a bibliographic database?
What is the structure of a database?
What is Ovid MEDLINE?
What are Boolean Operators?
What are wildcards?
Subject heading searching

Strategy:

Background

The Challenge: How to find useful information quickly?
Biomedical information repositories such as Ovid MEDLINE and Embase on Ovid, contain tens of millions of database records on past and currently available medical literature. Updated on a regular basis, they are large, diverse, highly structured and relentlessly dynamic general purpose resources. This can present challenges to health care professionals in clinical settings, for whom (a). only a sub-set of the database is relevant to them, and (b). they need to be able to quickly locate references that they can be sure are both clinically relevant and scientifically sound.

The Solution: Tested and trusted search filters
An important category of tried, tested and trusted database search filters are validated search filters. These are search strategies made available by subject matter and information experts who have constructed and developed them using a reference set of data as a ‘gold standard’. The resulting search filters are then tested against a test set of references in order to assess their effectiveness in terms of targeted and reliable information retrieval. Where they consistently exceed a certain threshold they are deemed ‘validated’. Although such search filters, as is here the case, may only be comprised of 4-6 search expression lines, the fact of their validation accords them a preferred status in terms of being an information retrieval option. In short, validated search filters are high quality, reliable ‘knowledge assists’ that help both clinicians and those that advise them on information retrieval matters, e.g. librarians and information specialists, to find useful information quickly.

The Source: Clinical Queries from McMaster University in Canada
As used here by Focused Searches, the phrase ‘clinical queries’ refers to database search filters that have been developed by the Health Information Research Unit (HIRU), based at McMaster University in Canada. Made available as part of their Hedges Project, the clinical query validated search filters cover dedicated ‘purpose categories’ surrounding human health disorders. The purpose categories are causation (etiology), course (prognosis), diagnosis, treatment and therapy, clinical predictions, the economics around human health disorders, studies of quality improvement of health services as well as continuing education of health care professionals. For fuller information on clinical queries, their origins as well as a list of accompanying references, please see  https://hiruweb.mcmaster.ca/hkr/hedges/ .

How to make best use of clinical queries?
This Focused Search presents the clinical query for the HIRU ‘purpose category’ Therapy, in three versions. The first version (see #1 in the table below), when used in combination with a human health disorder, has been tuned for maximized sensitivity. This is a broad search that will seek to return the highest proportion of relevant results pertaining to treatments and therapies related to the specified human health disorder. It may also include some less relevant results. By contrast its counterpart (see #2 in the table below) which is tuned for maximized specificity, constitutes a narrow search. It will seek to return the highest possible proportion of least relevant results. Being then such a targeted search, designed to include only the most relevant results, it may in doing so miss some of these otherwise wished for references. A third option (see #3 in the table below) is a search that has been tuned to seek a middle way between the broad and narrow search options, that is, to obtain the best balance between sensitivity and specificity.

Adapted from https://hiruweb.mcmaster.ca/hkr/hedges/medline/

Are these search filters still up to date?
Yes, the clinical query validated search filters are up to date. For further information, please refer to the publications listed in Re: Search Filter - Currency: in the References section below.

Why does the Focus Search display as a list of search lines?
The format of the rendered Focused Search for this clinical query is in two parts. The first part is a single line which contains all the clinical query’s relevant terms and expressions. The second part splits the constituent terms and expressions into their component sub-parts and then lists these line by line. At the bottom of the list of component sub-parts the OR operator is then used to obtain an overall result for all the terms and expressions in combination. This result should always be the same as the very first line. The aim of unpacking the clinical query line by line in this way is to ensure the purpose behind each line is understood as is the Ovid syntax used in the line’s construction.

Ovid Syntax Check

• An .mp or ‘multi-purpose’ search, searches across a set of default fields for the database.
• ‘pt’ stands for ‘publication type’, a specifically indexed field in Ovid MEDLINE.
• The character ‘:’ is a wildcard denoting truncation. Ovid now more usually uses ‘$’ or ‘*’.
• The expression ‘tu.xs’ indicates a search on the MeSH subheading ‘therapeutic use’, i.e. ‘tu’ including, as denoted by the command ‘.xs’, that subheading’s narrower terms.
• Search lines can be connected one after the other using the OR operator. Alternatively the search line can be grouped together using the expression ‘or/2-4’ where ‘or’ refers to the OR operator and  the numbers 2-4 refer to the search lines #2, #3 and #4.

Reviewers:

Primary: Michael Fanning

Secondary: Darlene Ennis

Review Date: 2024-07-15

Expiry Date: 2025-07-15

Original search produced by:

McMaster University

References:

Re: McMaster University, Health Information Research Unit, Hedges Project
For information on clinical queries, as well as a list of accompanying references, please see https://hiruweb.mcmaster.ca/hkr/hedges/

Re: Search Filter - Construction:
Haynes RB, McKibbon KA, Wilczynski NL, WalterSD, Werre SR; Hedges Team. Optimal search strategies for retrieving scientifically strong studies of treatment from Medline: analytical survey. BMJ. 2005 May 21;330(7501):1179. Epub 2005 May 13. Full text link: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC558012/pdf/bmj33001179.pdf

Re: Search Filter - Currency:
Navarro-Ruan T, Haynes RB. Preliminary comparison of the performance of the National Library of Medicine's systematic review publication type and the sensitive clinical queries filter for systematic reviews in PubMed. Journal of the Medical Library Association: JMLA. 2022 Jan 1;110(1):43. Full text link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8830395/

Wilczynski NL, McKibbon KA, Walter SD, Garg AX, Haynes RB. MEDLINE clinical queries are robust when searching in recent publishing years. Journal of the American Medical Informatics Association. 2013 Mar 1;20(2):363-8. Full text link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3638187/ 

OvidGO! / Skills Videos
What is a bibliographic database?
What is the structure of a database?
What is Ovid MEDLINE?
What are Boolean Operators?
What are wildcards?
Subject heading searching

Strategy:

Background

The Challenge: How to find useful information quickly?
Biomedical information repositories such as Ovid MEDLINE and Embase on Ovid, contain tens of millions of database records on past and currently available medical literature. Updated on a regular basis, they are large, diverse, highly structured and relentlessly dynamic general purpose resources. This can present challenges to health care professionals in clinical settings, for whom (a). only a sub-set of the database is relevant to them, and (b). they need to be able to quickly locate references that they can be sure are both clinically relevant and scientifically sound.

The Solution: Tested and trusted search filters
An important category of tried, tested and trusted database search filters are validated search filters. These are search strategies made available by subject matter and information experts who have constructed and developed them using a reference set of data as a ‘gold standard’. The resulting search filters are then tested against a test set of references in order to assess their effectiveness in terms of targeted and reliable information retrieval. Where they consistently exceed a certain threshold they are deemed ‘validated’. Although such search filters, as is here the case, may only be comprised of 4-6 search expression lines, the fact of their validation accords them a preferred status in terms of being an information retrieval option. In short, validated search filters are high quality, reliable ‘knowledge assists’ that help both clinicians and those that advise them on information retrieval matters, e.g. librarians and information specialists, to find useful information quickly.

The Source: Clinical Queries from McMaster University in Canada
As used here by Focused Searches, the phrase ‘clinical queries’ refers to database search filters that have been developed by the Health Information Research Unit (HIRU), based at McMaster University in Canada. Made available as part of their Hedges Project, the clinical query validated search filters cover dedicated ‘purpose categories’ surrounding human health disorders. The purpose categories are causation (etiology), course (prognosis), diagnosis, treatment and therapy, clinical predictions, the economics around human health disorders, studies of quality improvement of health services as well as continuing education of health care professionals. For fuller information on clinical queries, their origins as well as a list of accompanying references, please see  https://hiruweb.mcmaster.ca/hkr/hedges/ .

How to make best use of clinical queries?
This Focused Search presents the clinical query for the HIRU ‘purpose category’ Clinical Prediction Guides, in three versions. The first version (see #1 in the table below), when used in combination with a human health disorder, has been tuned for maximized sensitivity. This is a broad search that will seek to return the highest proportion of relevant results pertaining to treatments and therapies related to the specified human health disorder. It may also include some less relevant results. By contrast its counterpart (see #2 in the table below) which is tuned for maximized specificity, constitutes a narrow search. It will seek to return the highest possible proportion of least relevant results. Being then such a targeted search, designed to include only the most relevant results, it may in doing so miss some of these otherwise wished for references. A third option (see #3 in the table below) is a search that has been tuned to seek a middle way between the broad and narrow search options, that is, to obtain the best balance between sensitivity and specificity.

Adapted from https://hiruweb.mcmaster.ca/hkr/hedges/medline/

Are these search filters still up to date?
Yes, the clinical query validated search filters are up to date. For further information, please refer to the publications listed in Re: Search Filter - Currency: in the References section below.

Why does the Focus Search display as a list of search lines?
The format of the rendered Focused Search for this clinical query is in two parts. The first part is a single line which contains all the clinical query’s relevant terms and expressions. The second part splits the constituent terms and expressions into their component sub-parts and then lists these line by line. At the bottom of the list of component sub-parts the OR operator is then used to obtain an overall result for all the terms and expressions in combination. This result should always be the same as the very first line. The aim of unpacking the clinical query line by line in this way is to ensure the purpose behind each line is understood as is the Ovid syntax used in the line’s construction.

Ovid Syntax Check

• An .mp or ‘multi-purpose’ search, searches across a set of default fields for the database.
• ‘tw’ stands for ‘text word’, a field in Ovid MEDLINE covering both title (TI) and abstract (AB).
• The character ‘:’ is a wildcard denoting truncation. Ovid now more usually uses ‘$’ or ‘*’.
• Search lines can be connected one after the other using the OR operator. Alternatively the search line can be grouped together using the expression ‘or/2-4’ where ‘or’ refers to the OR operator and  the numbers 2-4 refer to the search lines #2, #3 and #4.

Reviewers:

Primary: Michael Fanning

Secondary: Darlene Ennis

Review Date: 2024-07-15

Expiry Date: 2025-07-15

Original search produced by:

McMaster University

References:

Re: McMaster University, Health Information Research Unit, Hedges Project
For information on clinical queries, as well as a list of accompanying references, please see https://hiruweb.mcmaster.ca/hkr/hedges/

Re: Search Filter - Construction:
Wong SS, Wilczynski NL, Haynes RB, Ramkissoonsingh R, Hedges Team. Developing optimal search strategies for detecting sound clinical prediction studies in MEDLINE. In AMIA Annual Symposium Proceedings 2003 (Vol. 2003, p. 728). American Medical Informatics Association. See https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1479983/

Re: Search Filter - Currency:
Navarro-Ruan T, Haynes RB. Preliminary comparison of the performance of the National Library of Medicine's systematic review publication type and the sensitive clinical queries filter for systematic reviews in PubMed. Journal of the Medical Library Association: JMLA. 2022 Jan 1;110(1):43. Full text link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8830395/

Wilczynski NL, McKibbon KA, Walter SD, Garg AX, Haynes RB. MEDLINE clinical queries are robust when searching in recent publishing years. Journal of the American Medical Informatics Association. 2013 Mar 1;20(2):363-8. Full text link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3638187/ 

OvidGO! / Skills Videos
What is a bibliographic database?
What is the structure of a database?
What is Ovid MEDLINE?
What are Boolean Operators?
What are wildcards?
Subject heading searching

Strategy: