Can We Believe the Claims

B1, Topic 3.2 How Science Works

Can we believe the claims?

Aims Students are presented with some data from a scientist who is working for a company making a spread. The company claims that the spread reduces blood cholesterol. Students are asked questions regarding the repeatability, reproducibility, validity and bias of the study. They are also asked how the study could be made more repeatable and reproducible.

About this activity Students should know about cholesterol and its link to heart disease. They should also know that statins are drugs used to lower cholesterol levels. This activity requires an appreciation of how scientific research can be seriously biased and flawed if the researchers have got something to gain.

Teaching notes 1 This activity could be used as the basis of a class discussion. It may bring up issues not given in the answers which could also be used in discussion. 2 It is intended that differentiation would be through outcome as more detailed answers may be given by more able students, although the basic concept of bias should be accessible to all. 3 It may be good to give details of other studies where evidence has been under scrutiny or ask students to find some out for homework.

Answers to questions 4 Students may come up with a number of suggestions including: small sample size, study period too short, lack of information about the volunteers and their diet, age, sex, lifestyle. 5 The study does not control any other aspect of their diet. 6 Mr White may be biased as he is being paid by the company who want good results for their advertising. 7 Volunteers are being paid to say they have followed the instructions, therefore they may lie. 8 The fact that some of the group were also on statins means their cholesterol levels would be lowered anyway. 9 Any sensible suggestions which improve on the study given.