The purpose of this paper is to provide a systematic approach to the pre-testing, and hence, the validation of postal and electronic questionnaires. The pre-test instrument was first used on a research project that gathered data on the composition of environmental financial information, user groups and the decision effectiveness of different information displays. The theoretical modelling of relationships was extensive and as a consequence the research method chosen needed to be both broadly based and capable of providing the required data. The approach provides assistance to the researcher and will form the basis of instrument reliability. The implication of using the suggested approach in this paper is the strengthening of questionnaires and the greater level of reliability.