A permanent set of experimental units used in marketing research investigations is known as panel .Panel can be used both for exploratory and conclusive research. In such experiments observation are recorded at some pre determined intervals of time and experimental variables can be introduced it and when desired. Here any two set of successive measurements between which some experimental variable is introduced can be considered as before and after experimental measurements.For the method to be effective the experimenter must know in advance the trend in case the experimental variable is not administered on the subjects.Panel designs can be used in developing early forecasts of ling run sales for new products. The followings are the main advantages of panel design: a.More detailed analysis is available,b. More data can be obtained,c. The accuracy can be higher and costs can be lower,d. The valid conclusion of r the situation number investigation can be drawn,e. The design itself guides for the procedure for collecting the observations as well as the use of measure s for analysis.
Simple Test Series Experiments: Some dealers or retailers are selected for recording s observations over certain period of time e g, study the impact of some advertising policy on sales a one may select some dealer or retailers. The sales during a certain period before the advertisement and after the advertisement are recorded. The sales recorded can be analyzed to study the impact of advertising policy on sales promotion.
Recurrent Time Series Design: Here the advertising policy is introduced removed and reintroduced over different period of time and the sales over these periods are recorded.