Misleading description

Relative effects

Look out for nutrition intervention effects that are described as relative effects.

Relative effects (ratios) alone don’t provide enough information for judging the importance of the difference between groups in a comparison of interventions. Relative effects may also give the impression that a difference is more important than it actually is.

For example, if a nutrition intervention cuts the likelihood of getting an illness in half and the baseline risk of a person getting this illness is 2 in 10, receiving the nutrition intervention may be worthwhile, even if it also has some harmful side-effects. If, however, the risk of getting the illness is 2 in 10,000, then receiving the intervention may not be worthwhile even though the relative effect is the same. The absolute effect of a nutrition intervention (the difference) is likely to vary for people with different baseline risk.

REMEMBER: Don’t be tricked by relative effects. Always consider the absolute effects of nutrition interventions.