Grey Lit Searching for Dummies

Ah, grey literature! Confronted with a vast void of faceless, nameless literature, it’s easy to quickly become overwhelmed. Where do I start? What do I search? What am I even looking for?

As a medical librarian, I’m used to structured searches in curated databases, and going into the unknown can be a frightening thought. However, it is possible to add structure to a grey literature search!

First: What are you looking for?

Too often, the idea of “grey literature” is lumped into one monolithic term. In reality, grey literature is a broad umbrella term and encompasses a lot of different document types whose main commonality is that they are unpublished or published outside traditional publishers: basically, anything that’s not a traditional published research article.

Think about the research project at hand and what types of literature would best support it. For example, in a qualitative synthesis or realist review of a social sciences topic, a lot of robust evidence might come from book chapters with unpublished studies. In a mapping review in health services research, government white papers/reports about local health initiatives might be most relevant. What do you expect the evidence to look like, and where might you go about finding it?

  • Reports or white papers
  • Theses and dissertations
  • Book chapters
  • Clinical trials registers
  • Conference proceedings

Second: Make a plan!

Next, make a detailed plan for searching the literature. Your searching plan should contain information about what sources will be searched, how they will be searched, how the searches will be documented, and how/where the potentially relevant documents will be downloaded/stored.

Some strategies to consider including in your plan might be:

  • Traditional database searches that will include grey lit such as conference abstracts (e.g. PyscINFO, Embase, Proquest Theses and Dissertations)
  • Specialised databases (e.g. “grey” databases such as OpenGrey or HMIC, or small subject-specific databases without sophistocated search mechanisms)
  • Search engines (e.g. Google, GoogleScholar, DuckDuckGo)
  • Custom Google search engines (e.g. NGOs search, Just State Web Sites; Think Tank Search)
  • Clinical Trials registers
  • Hand searching of key subject websites (e.g. the main associations or government departments in that topic area)
  • Consultation with experts (who may have ideas about papers you have missed)

For each strategy, document all the details you will need to conduct the search:

  • Who is going to conduct the search?
  • What search terms or search strategies will be used?

For more sophistocated sites, a full boolean strategy might be used, but for a site with a simple search box, perhaps one term or a few terms at a time might need to be used. Strategies should be similar, but adapted for the searching capabilities of that resource.

Think also about the context: if your search topic is “yoga for substance abuse”, and you’re searching the NIDA International Drug Abuse Research Abstract Database, you won’t need to include substance abuse terminology in your searches, because everything in that subject database is already about substance abuse.

  • How will the searches be documented? Oftentimes, an excel spreadsheet will suffice with information such as the person searching, the date, the searching strategy, number of items looked at, and the number of items selected as potentially relevant. Bear in mind that for some resources, the searching strategy might be narrative, such as “clicked the research tab and browsed the list of publications”.
  • How many results will you look at? The first 50? The first 100? Until there are diminishing returns?

Third: Execute the plan!

Make sure to have a strategy in place for recording your searches and downloading your citations. Due to the transient nature of the web, grey literature searches generally aren’t replicable. When you search google one week, and conduct the same search a year later, you might get different results. However, searches for grey literature can and should be transparent and well-documented, such that someone else could conduct the same searches at a later point, even if they would get different results.

For more information, check out the following papers:

Briscoe S. Web searching for systematic reviews: a case study of reporting standards in the UK Health Technology Assessment programme. BMC research notes. 2015 Apr 16;8(1):153.

Godin K, Stapleton J, Kirkpatrick SI, Hanning RM, Leatherdale ST. Applying systematic review search methods to the grey literature: a case study examining guidelines for school-based breakfast programs in Canada. Systematic reviews. 2015 Oct 22;4(1):138.

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Quick tip: use the Ovid multi-line launcher

In the “multi-line” vs “single line” searches debate, one point that is often thrown around is: multi-line searches are more cumbersome to edit and run. Even with Ovid’s new “edit” button, it still takes a few clicks and a few page refreshes to edit a strategy and see the results. When making lots of changes quickly to a strategy, this time can really add up.

One underappreciated and little known tool is Ovid’s mutli-line launcher. It’s beautiful! The multi-line launcher allows a user to copy/paste a multi-line strategy directly into the search box, press enter, and view the search results – with hits for each line – as normal.

Ovid-multi-line-launcher
screenshot of Ovid’s multi-line launcher tool

When making edits to a strategy I tend to do the following:

  1. paste the strategy into the multi-line launcher box
  2. ensure that the line numbers are still correct or changed if needed
  3. press enter to view results
  4. if strategy requires a change, type “..pg all” into the search box in the main Ovid MEDLINE interface to delete search history (see more about keyboard shortcuts in Ovid here)
  5. Make edits to the strategy in a word document
  6. Paste back into the multi-line launcher box

I’ve found this strategy works more quickly and with less site time-outs than using the native “edit” button.

Try it here: http://demo.ovid.com/demo/ovidsptools/launcher/launcher.html

How to convert a search between PubMed and Ovid

Have you ever tried to convert a search strategy from PubMed to Ovid or vice versa? It can be a real pain. The field codes in Ovid don’t always nicely match up with the tags in PubMed and it can be difficult to wrap your head around the auto-expode in PubMed vs manual explode in Ovid for indexing terms. Not to mention that there is some functionality that exists in Ovid but not PubMed (such as proximity operators) and in PubMed that doesn’t exist in Ovid (such as the supplementary concepts tag). Yikes!

Why would you want to convert a search strategy between the two, you ask? Don’t they have the same content?

  1. There is some content that is in PubMed but not Ovid MEDLINE. The NLM factsheet “MEDLINE, PubMed, and PMC (PubMed Central): How are they different?” gives an overview of PubMed’s unique content.
  2. You might want to use features that are available in both databases! Maybe you’re working on a strategy in Ovid MEDLINE, but realise partway through you’d really like to use one of the PubMed subject filters, for example.
  3. Sometimes, you might find a search filter or hedge, but it is written in the syntax of a different interface. Translating a strategy isn’t always easy or intuitive, so automated the process can reduce errors and save time.

Over the past few months, I’ve been working with a colleague to build a tool that automatically converts searches between the two interfaces, and we recently presented our work at the EAHIL/ICML conference in Dublin.

2A488B84-64F4-44B6-BF9A-A87D41BBCCF3
EAHIL/ICML conference in Dublin

During the conference week, we had dozens of excellent conversations in person and on Twitter, and 138 unique website visitors! Thanks to everyone who provided feedback and suggestions for improvements. We are working hard to incorporate many of them over the coming months.

The tool is freely available at medlinetranspose.github.io. Please feel free to check it out and let us know how it works for you!