study", International Journal of Production Economics, 45 (1-3), 293–302, Nahmias, Steven (2005) Production & Operations Analysis, Fifth Edition, McGraw-Hill. Trigg, D.W. (1964) "Monitoring a forecasting system". Operational Research Quarterly, 15, 271–274. Trigg, D.W. and Leach, A.G. (1967). "Exponential smoothing with an adaptive response rate". Operational Research Quarterly, 18 (1), 53–59 Mita Montero, J David (1973). "Análise de Sistemas de Previsão - Amortecimento Exponencial". Tese de Mestrado de Engenharia Industrial PUC-RJ,Brasil. Aplicação Industrial de Tracking Signal. External links Tracking signal in forecasting by Dr Muhammad Al-Salamah Tracking Signal:A Measure of Forecast Accuracy by Tyler Hedin, Brigham Young University (Powerpoint) Statistical deviation and dispersion Time series Management science Statistical forecasting