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Effective forecasting and judgmental adjustments: an empirical evaluation and strategies for improvement in supply-chain planning

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  • Fildes, Robert
  • Goodwin, Paul
  • Lawrence, Michael
  • Nikolopoulos, Konstantinos

Abstract

Demand forecasting is a crucial aspect of the planning process in supply-chain companies. The most common approach to forecasting demand in these companies involves the use of a computerized forecasting system to produce initial forecasts and the subsequent judgmental adjustment of these forecasts by the company's demand planners, ostensibly to take into account exceptional circumstances expected over the planning horizon. Making these adjustments can involve considerable management effort and time, but do they improve accuracy, and are some types of adjustment more effective than others? To investigate this, we collected data on more than 60,000 forecasts and outcomes from four supply-chain companies. In three of the companies, on average, judgmental adjustments increased accuracy. However, a detailed analysis revealed that, while the relatively larger adjustments tended to lead to greater average improvements in accuracy, the smaller adjustments often damaged accuracy. In addition, positive adjustments, which involved adjusting the forecast upwards, were much less likely to improve accuracy than negative adjustments. They were also made in the wrong direction more frequently, suggesting a general bias towards optimism. Models were then developed to eradicate such biases. Based on both this statistical analysis and organisational observation, the paper goes on to analyse strategies designed to enhance the effectiveness of judgmental adjustments directly.

Suggested Citation

  • Fildes, Robert & Goodwin, Paul & Lawrence, Michael & Nikolopoulos, Konstantinos, 2009. "Effective forecasting and judgmental adjustments: an empirical evaluation and strategies for improvement in supply-chain planning," International Journal of Forecasting, Elsevier, vol. 25(1), pages 3-23.
    • Handle: RePEc:eee:intfor:v:25:y:2009:i:1:p:3-23
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    1. Buehler, Roger & Griffin, Dale, 2003. "Planning, personality, and prediction: The role of future focus in optimistic time predictions," Organizational Behavior and Human Decision Processes, Elsevier, vol. 92(1-2), pages 80-90.
    2. Thomas Åstebro & Samir Elhedhli, 2006. "The Effectiveness of Simple Decision Heuristics: Forecasting Commercial Success for Early-Stage Ventures," Management Science, INFORMS, vol. 52(3), pages 395-409, March.
    3. Deschamps, Elaine, 2004. "The impact of institutional change on forecast accuracy: A case study of budget forecasting in Washington State," International Journal of Forecasting, Elsevier, vol. 20(4), pages 647-657.
    4. Lee, Wing Yee & Goodwin, Paul & Fildes, Robert & Nikolopoulos, Konstantinos & Lawrence, Michael, 2007. "Providing support for the use of analogies in demand forecasting tasks," International Journal of Forecasting, Elsevier, vol. 23(3), pages 377-390.
    5. Kottemann, Jeffrey E. & Davis, Fred D. & Remus, William E., 1994. "Computer-Assisted Decision Making: Performance, Beliefs, and the Illusion of Control," Organizational Behavior and Human Decision Processes, Elsevier, vol. 57(1), pages 26-37, January.
    6. Gardner, Everette S. & Anderson, Elizabeth A., 1997. "Focus forecasting reconsidered," International Journal of Forecasting, Elsevier, vol. 13(4), pages 501-508, December.
    7. Lawrence, Michael & Goodwin, Paul & O'Connor, Marcus & Onkal, Dilek, 2006. "Judgmental forecasting: A review of progress over the last 25 years," International Journal of Forecasting, Elsevier, vol. 22(3), pages 493-518.
    8. Yelland, Phillip M., 2006. "Stable seasonal pattern models for forecast revision: A comparative study," International Journal of Forecasting, Elsevier, vol. 22(4), pages 799-818.
    9. Harvey, Nigel, 1995. "Why Are Judgments Less Consistent in Less Predictable Task Situations?," Organizational Behavior and Human Decision Processes, Elsevier, vol. 63(3), pages 247-263, September.
    10. Moon, Mark A. & Mentzer, John T. & Smith, Carlo D., 2003. "Conducting a sales forecasting audit," International Journal of Forecasting, Elsevier, vol. 19(1), pages 5-25.
    11. Lawrence, Michael & O'Connor, Marcus & Edmundson, Bob, 2000. "A field study of sales forecasting accuracy and processes," European Journal of Operational Research, Elsevier, vol. 122(1), pages 151-160, April.
    12. Goodwin, Paul, 2000. "Improving the voluntary integration of statistical forecasts and judgment," International Journal of Forecasting, Elsevier, vol. 16(1), pages 85-99.
    13. Goodwin, Paul & Lawton, Richard, 1999. "On the asymmetry of the symmetric MAPE," International Journal of Forecasting, Elsevier, vol. 15(4), pages 405-408, October.
    14. Sanders, Nada R. & Ritzman, Larry P., 1992. "Journal of behavioral decision making: "The need for contextual and technical knowledge in judgmental forecasting", 5 (1992) 39-52," International Journal of Forecasting, Elsevier, vol. 8(4), pages 651-652, December.
    15. Gardner, Everette Jr., 2006. "Exponential smoothing: The state of the art--Part II," International Journal of Forecasting, Elsevier, vol. 22(4), pages 637-666.
    16. Robert Fildes & Paul Goodwin, 2007. "Against Your Better Judgment? How Organizations Can Improve Their Use of Management Judgment in Forecasting," Interfaces, INFORMS, vol. 37(6), pages 570-576, December.
    17. Yaniv, Ilan, 2004. "Receiving other people's advice: Influence and benefit," Organizational Behavior and Human Decision Processes, Elsevier, vol. 93(1), pages 1-13, January.
    18. Lim, Joa Sang & O'Connor, Marcus, 1996. "Judgmental forecasting with time series and causal information," International Journal of Forecasting, Elsevier, vol. 12(1), pages 139-153, March.
    19. Fildes, Robert & Bretschneider, Stuart & Collopy, Fred & Lawrence, Michael & Stewart, Doug & Winklhofer, Heidi & Mentzer, John T. & Moon, Mark A., 2003. "Researching Sales Forecasting Practice: Commentaries and authors' response on "Conducting a Sales Forecasting Audit" by M.A. Moon, J.T. Mentzer & C.D. Smith," International Journal of Forecasting, Elsevier, vol. 19(1), pages 27-42.
    20. Willemain, Thomas R., 1991. "The effect of graphical adjustment on forecast accuracy," International Journal of Forecasting, Elsevier, vol. 7(2), pages 151-154, August.
    21. Lawrence, M. & O'Connor, M., 1996. "Judgement or models: The importance of task differences," Omega, Elsevier, vol. 24(3), pages 245-254, June.
    22. Belton, Valerie & Goodwin, Paul, 1996. "Remarks on the application of the analytic hierarchy process to judgmental forecasting," International Journal of Forecasting, Elsevier, vol. 12(1), pages 155-161, March.
    23. McNees, Stephen K., 1990. "The role of judgment in macroeconomic forecasting accuracy," International Journal of Forecasting, Elsevier, vol. 6(3), pages 287-299, October.
    24. Flyvbjerg,Bent & Bruzelius,Nils & Rothengatter,Werner, 2003. "Megaprojects and Risk," Cambridge Books, Cambridge University Press, number 9780521009461, September.
    25. Yossi Aviv, 2001. "The Effect of Collaborative Forecasting on Supply Chain Performance," Management Science, INFORMS, vol. 47(10), pages 1326-1343, October.
    26. Armstrong, J. Scott & Collopy, Fred, 1992. "Error measures for generalizing about forecasting methods: Empirical comparisons," International Journal of Forecasting, Elsevier, vol. 8(1), pages 69-80, June.
    27. Bonaccio, Silvia & Dalal, Reeshad S., 2006. "Advice taking and decision-making: An integrative literature review, and implications for the organizational sciences," Organizational Behavior and Human Decision Processes, Elsevier, vol. 101(2), pages 127-151, November.
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