Do you immediately restrict your journal literature searches to English-only? While this is a valid strategy for many searches, it might not be appropriate for a systematic review.
Searching, compiling, screening, and interpreting publications for a review is already challenging enough without the added complication of a language barrier, and while it is common to see English-language restrictions in systematic reviews, this practice risks “language bias.” The risk of bias is especially problematic in systematic reviews on alternative medicine topics. Systematic reviews are often used to inform clinical decision making, so it is important for researchers to offer a complete assessment of the available research. The Cochrane Handbook states that searches should be conducted without language restrictions and inclusion decisions made on a case-by-case basis. That said, it is unlikely that reviewers will embark on learning a new language for a single review, so where does that leave you? Consider one of these suggestions:
The ability to read another language does not guarantee you will understand the complex medical terminology in that language. If your budget allows, hire an expert in medical translation to ensure quality specialty translation.
Are there people in your field, department, or program who are fluent in languages other than English? You may even have someone on your review team who already speaks another language. Create a team with language skillsets to make your review stronger.
Students who are majoring in a language other than English may be interested in article translation. Reaching out to language departments on campus can be an affordable (or sometimes free) option.
In some cases, you may be able to contact the publisher or author to see whether an English translation already exists. If they cannot provide an English translation, you may still be able to get information about the data collected directly from the source.
The Cochrane TaskExchange allows teams to request various tasks on an open board. You can create a bulk request for translating multiple records in the same language, but if searching for translations for multiple languages, you will need to make separate requests for each language. You do not have to pay for the services on Cochrane TaskExchange, but there is an expectation to contribute your skills elsewhere.
Some people find success using automatic translation software. The issue of properly translating medical terminology remains, but Google Translate can be an especially useful tool when translating for title/abstract screening. The automatic translation may help you determine whether an article meets your pre-determined inclusion/exclusion criteria. Once you have a set of articles for full-text screening, utilizing human translation services would be preferable.
Translating non-English records is the second step in the process. The first? Include databases with global reach to be truly comprehensive. Searching the International Clinical Trials Registry Platform (ICTRP) and databases like Latin American and Caribbean Health Sciences Literature (LILACS) will give you a more comprehensive view of the global literature landscape and will make your review stronger.