Purpose: The purpose of the thesis is to explore optimization of the demand planning process with focus on the judgmentally adjusted forecasting approach. The exploration of the system operator perspectives was focused upon for potential optimization actualization. As demand planning is an essential supply chain management process, this thesis contributes to the supply chain management literature and practice by supporting improved sustainable balancing of supply and demand plans. This retains sustainability implications, thus also contributing to the domain of sustainable supply chain management.

Method: A case study research design was applied involving a large Swedish manufacturer that utilizes the forecasting approach in question. Data collectiontechniques involving participant observations, several types of interviews, anddocument analysis were utilized. Analysis methods included reiterative thematic analysis and Design of Experiment. Software based coding through mixed inductive and deductive approach was conducted for deriving themes and variables which werefurther analyzed by full factorial simulation experiments.

Findings: Several themes were identified in the data in which challenges, benefits, and improvement potentials were identified and encapsulated in a framework based on system operator perspectives. Through statistical experimental analysis, it appeared that taking these system operator perspectives into consideration for demand planning process optimization can constitute promising potentials. These include correctidentification of relevant refinement variables for enhancing the system forecast adjustments quality.

Implications: Identifying challenges leads to mitigation. Understanding benefits allows for enhancement. Exploring improvement potentials leads to actualization. Hence, the demand planning process, in regard to this approach, would be optimized. With optimization, it would be easier to maintain the right levels of inventory, order numbers and quantities, and transportation miles, while increasing service levels by minimized backorders. Therefore, sustainability is to be supported by minimized costs and elevated service levels (economic sustainability), enhanced operational and logistics planning (environmental sustainability), and taking workers’ perspectives into consideration to improve their work task and serve customer needs better (social sustainability).

Limitations: As is the case with research involving interviews, participant perspective involves perception filters that can dim the objectivity of the findings. This, however, was mitigated by applying quantitative data gathering and analysis. The forecasting approach explored is especially suitable for planning demand of components like spare parts. Similarly, other types of assortments and forecasting approaches can be explored for demand planning process optimization.