Module: Epidemiology and Statistics

Topic 9


Topic 9: Why did the Advertising Standards Agency ban a TV advert for Actimel in 2009?

Objectives

When you have completed the reading and participated in the taught components for this week, we hope you will be able to

  • Formulate a question using the PICO (Population, Intervention, Comparator, Outcome) principle
  • Describe the key features of a systematic review
  • Explain what is meant by external validity of randomised trial 

 

Lecture

In 2009 the Advertising Standards Authority banned a TV advert for the probiotic yogurt drink Actimel because it claimed it was scientifically proven to ‘support your kids defences’. Starting with this example we will explain the formulation of questions for a systematic review and meta-analysis, using the PICO(S) principle. Using two reviews of probiotics carried out by the Cochrane centre, we will revise methods of summarising outcomes and how to interpret forest plots. 

Seminar

In this seminar, you will look at different ways outcomes can be measured, including quality of life. You will discuss the implications of numerous different outcomes in a single trial and across trials of the same intervention.

You will then critically appraise the report of a systematic review using the CASP checklist.

Click here to see the questions for seminar 9

Preparation for this week

Before the lecture

Look at the article on the BBC website. You can also watch some of the older adverts in full on www.youtube. Write down what you think are the health benefits being portrayed and how might these be measured.

Look at the Cochrane review by Hao. Read the abstract first and then look at how teh report is structured and what is contained in each part. In the lecture we will be looking at figure 1.1 in more detail. It woudl be useful to look at this figure before the lecture and write down any questions you may have about interpreting the data. 

 For the seminar

Read the paper by Hempel and carry out a critical apprasial using the CASP checklist. Bring the paper and checklist to the seminar.

Set Reading

BOOK CHAPTERS

  • Greenhalgh T. How to read a paper . Chapter 8 Papers that summarise other papers  Avaliable free online (although chapters are not numbered)

ACADEMIC PAPERS

Note: Cochrane reviews are very long and detail every paper assessed for eligibility. These are best viewed on-line initially. You might find it useful to print the abstract and some specific parts but it is not necessary to print out the whole document.

 

WEB SITES

 

 

Lecture Notes and Powerpoints