Home > About Testing Treatments international (TTi)

About Testing Treatments international (TTi)

Why was Testing Treatments written?

A collage of claims

Claims about what might improve or harm health are everywhere.

Many treatment claims are untrustworthy, however.  Unwarranted faith in untrustworthy claims causes people to suffer by using ineffective or harmful treatments, or failing to use effective ones.

"Teach a woman to fish.."

Teaching people to fish is better than giving them fishes! If you need advice on specific treatment claims, try these resources.

Unfortunately, it is often hard to tell whether a treatment claim is untrustworthy. Skills are needed to spot claims that are unreliable.

Testing Treatments international (TTi) provides open access to learning resources for people who want to (or help others to) acquire those skills.

Please note that TTi is NOT for specific advice on particular treatments.  This information is available elsewhere.

However, TTi SHOULD help to promote critical thinking about the treatment claims that people encounter.

TTi builds on Testing Treatments, a successful book written for the public, which is available to download for free in more than a dozen languages (see  the top of the page).

Testing Treatments is for anyone who wishes to learn how to assess the trustworthiness of treatment claims.

What’s TTi?

When the 2nd edition of Testing Treatments was published in 2011 we wanted to make the text of the book readily available, so we launched a website – Testing Treatments interactive (TTi) – from which the text of the book could be freely downloaded.

One indication of the continuing relevance of Testing Treatments is that the book has been translated into many languages, with each translation being hosted for free download from a TTi ‘sibling website’ in each of the languages represented (see www.testingtreatments.org). To celebrate this multilingual reality, we now see TTi as an abbreviation of Testing Treatments international.

Since its launch in 2011, TTi-English has undergone several cycles of development, evaluation with users, and further development. Reflecting user comments, the 2018 design is simpler than some earlier versions. Like the book it hosts, TTi-English is for anyone who wishes to learn how to assess the trustworthiness of treatment claims.

What’s in TTi-English besides the text of Testing Treatments?

A pupil

Supporting the use of evaluated resources in teaching critical thinking about treatment choices.

TTi-English has been designed to enable visitors to read or listen to readings of all or some of the text of Testing Treatments. In addition, it provides access to additional learning resources contained in the Critical thinking and Appraisal Resource Library (CARL), identifying those that have been formally evaluated.

These additional learning resources are available in a variety of formats: text, video, audio, lessons, cartoons, and website pages.

Information about the creation of CARL is available in Castle et al. 2017.

How are Key Concepts used to organise material in TTi-English?

The material in the website is organised to reflect over 30 Key Concepts relevant to assessing the trustworthiness of claims about the effects of treatments.

Our definition of ‘treatments’ includes any action intended to improve health or relieve suffering. These include changes in behaviour; screening programmes; drugs, surgery, physical and psychological treatments; and public health and healthcare system changes.

The Key Concepts developed by the Informed Health Choices project have been grouped under three headings:

Can visitors test their understanding of Key Concepts?

Snake oil salesman

Can you tell snake oil from shinola? Take our test and find out

If you want a foretaste of the kind of evaluation questions that have been developed and validated by the Informed Health Choices project, try our illustrative fun quiz.

This quiz will give you an idea of the format of the The Claim Evaluation Tools, which have been formally evaluated to assess people’s understanding of the Key Concepts needed to assess the trustworthiness of treatment claims.


  • Austvoll-Dahlgren A, Semakula D, Nsangi A, Oxman A, Chalmers I, Rosenbaum S, Guttersrud Ø, and the IHC Group. Measuring ability to assess claims about treatment effects: the development of the ‘Claim Evaluation Tools’. BMJ Open 2016;6:e013184. doi:10.1136/bmjopen-2016-013184
  • Castle JC, Chalmers I, Atkinson P, Badenoch D, Oxman AD, Austvoll-Dahlgren A, Krause K, Schwartz LM, Woloshin S, Burls A, Mosconi P, Nordheim L, Hoffmann T, Cusack L, Albarqouni L, Glasziou P. Establishing a library of resources to help people understand Key Concepts in assessing treatment claims – The Critical thinking and Appraisal Resource Library (CARL). July 2017.  https://doi.org/10.1371/journal.pone.0178666http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0178666.
  • Chalmers I, Oxman AD, Austvoll-Dahlgren A, Ryan-Vig S, Pannell S, Sewankambo N, Semakula D, Nsangi A, Albarqouni L, Glasziou P, Mahtani K, Nunan D, Heneghan C, Badenoch D. Key Concepts for Informed Health Choices: a framework for helping people learn how to assess treatment claims and make informed choices. BMJ Evid Based Med 2018 23:29-33. doi: 10.1136/ebmed-2017-110829.

Image credits

  • Teaching Allie to Fish, Ted Kerwin, CC BY 2.0