A comparison of the relative sensitivity of two types of Heaf gun

A total of 696 secondary school children were given a Heaf test in one forearm with a magnetic head Heaf gun and in the other forearm with a fixed head gun. One week later the results were read blind. In 333 (48%) children the fixed head gun gave a more strongly positive result than the magnetic head gun, while in only 27 (4%) children did the magnetic head gun gives a more strongly positive result. These findings are statistically highly significant (p less than 0.001).