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Systematic Reviews: Grey Literature

A guide to finding resources for a systematic review in the health and medical sciences

What is Grey Literature?

Grey literature refers to both published and unpublished research material that is not available commercially. It can be the best source of up-to-date research on some topics. e.g Statistics relating to Australian health. Note however that grey literature is usually not subject to peer review and must be evaluated accordingly. Grey literature can be found by searching the internet, databases, institutional repositories and catalogues. 

Grey literature consists of:

  • reports (reports of government and research organisations, are generally freely available on the internet) 
  • theses
  • conference proceedings
  • technical specifications & standards
  • translations
  • bibliographies 
  • technical & commercial documention 
  • official documents  

Alberani, V., De Castro Pietrangeli, P. & Mazza, A.M.  (1990).  The use of grey literature in health sciences: A preliminary survey.  Bulletin of the Medical Library Association, 78 (4) : 358-363. Retrieved from 

Tips for Searching for Grey Literature

In addition to the sources listed above, internet searching can locate other useful sources:

  • If looking for information on grey literature in general, remember there are two spellings and search for (gray OR grey) literature
  • Find and search the online catalogues of large libraries
  • Conference papers or conference proceedings can be difficult to track down - search for the host sites of conferences and academic associations
  • You can search for conference papers in SCOPUS or Web of Science databases.
  • Try restricting your search to the .org and/or .gov domains, for example: site: .gov, site:, site: .org or restrict to a PDF documen, filetype: pdf

Evaluating Grey Literature

A checklist for evaluating grey literature has been developed by Jess Tyndall, Flinders University.

It uses AACODS (Authority, Accuracy, Coverage, Objectivity, Date and Significance) to evaluate grey literature materials.

  • Authority - Is the author credible?
  • Accuracy -  Is it supported by documented and authoritative references? Is there a clearly stated methodology? Is it in line with other work on the same topic
  • Coverage - Have limitations been imposed and are these stated clearly?
  • Objectivity - Can bias be detected?
  • Date - Can't find the date? Rule of the thumb is to avoid such material
  • Significance - Is it relevant? Would it enrich or have an impact on your research?

For a full version of this checklist please see this document. 

Useful sources

Australian Bureau of Statistics and CURF microdata

Australian Bureau of Statistics (CURFS - Confidentialised Unit Record Files)

All ECU researchers have access to the CURFS database.

If you need detailed ABS survey information, search within the ABS database for CURFS & register to use. 

What is CURF microdata?

Confidentialised Unit Record Files (CURFs) are microdata files containing individual responses, which have been treated to protect privacy and confidentiality using a range of statistical techniques. There are two types of CURFs:

BASIC CURFS are designed for use in the researcher's own environment. There are over 100 basic CURFs available, covering many ABS social surveys, the Census of Population and Housing and some business data. Individual data items in basic CURFs are likely to be reported at a broader level than that offered in other ABS microdata products. Basic CURFs are available in MicrodataDownload.

EXPANDED CURFS have been designed for use in the secure DataLab and Remote Access Data Laboratory (RADL) environments. Due to these protected environments, researchers are able to access finer levels of detail than on a basic CURF.

Why is microdata confidentialised?

The ABS takes its responsibilities to protect the confidentiality of individuals' and organisations' data very seriously. This is fundamental to the trust the Australian public has in the ABS, and that trust is, in turn, fundamental to the excellent quality of ABS information. Without that trust, survey respondents may be less forthcoming or truthful in answering our questionnaires.

How are microdata confidentialised?

The most basic of the techniques employed by the ABS involves removing all identifying information, such as names and addresses.
Additionally, the data items that are most likely to enable identification of unit records are only released in broad categories. For example, while survey questionnaires may capture your home or business address, microdata may only be released at the State or Territory level.

More advanced confidentialisation occurs through checking the CURFs for records with uncommon combinations of responses. These records may be altered slightly to ensure individual respondents cannot be identified.

For more information, see 'Avoiding Inadvertent Disclosure' and 'Microdata' on our web page How the ABS keeps your information confidential.


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