In the sciences the examination groups have largely decided that teacher assessment shall be of practical work. The aim is to increase the validity of the assessment; and in particular to capture ephemeral evidence such as observing safety precautions, using the right technique when handling equipment, engaging in verbal debate and working with others. Aims and objectives in science have now been expressed in more subject-specific terms making them easier to use and understand. Coursework is ideal for assessing practical skills, and in the sciences is identical with practical work for most examining groups, who, with few exceptions, have not taken advantage of coursework to assess such areas as technological and socio-economic issues. The Northern Examining Association science scheme, for example, is very thorough requiring an assignment record sheet listing the assignments which have been used and the skills assessed in each, and an individual record card giving the assignments and the marks awarded for each skill.