Application of a design of multiple time series to a case of intervention in two classrooms of primary education.

Application of a design of multiple time series to a case of intervention i n two classrooms of primary education. In the designs of interrupted time s eries carried out with a single subject, two main difficulties appear. The first one lies in the fact that it isn't quite clear whether the changes, w hich appear in the execution, are due to the circumstances introduced by th e investigator (treatment) or to other circumstances that may occur at the same time. The second one consists in the difficult generalization of the r esults obtained from a single subject. In this work, we present a case to w hich we have applied the extension of the interrupted time series design an alysis technique (ARIMA models) (Vallejo & Escudero, 1998) with slight modi fications, and extending it to the use of several answer variables register ed during the treatment.