In reviewing the PLE data, Elizabeth Burke noticed that defects received from suppliers have decreased. Upon investigation, she learned that in 2010, PLE experienced some quality problems due to an increasing number of defects in materials' received from suppliers. The company instituted an ini-tiative in August 2011 to work with suppliers to reduce these defects, to more closely coordinate deliveries, and to improve materials quality through reengineering supplier production policies. Elizabeth noted that the program ap-peared to reverse an increasing trend in defects; she would like to predict what might have happened had the supplier initiative not been implemented and how the number of defects might further be reduced in the near future.
What would be the best analysis to use to forecast where the company would have been if they did not implement a change assuming the use of XLMiner? We have the data available for the first 20 months prior to implementation. Can the same analysis be used to forecast where the company will be in the next few months?