## 1 Introduction
In this context, the success of the parties within a supply chain will be determined in the future by the ability to identify disturbances early to compensate for such issues with adequate planning models that ensure a high quality of planning [21]. In this context, sales and operations planning (S&OP) can improve an organization's alignment with its suppliers and customers, leading to positive effects on operational performance. Although S&OP practices are associated with positive effects, it is not clear how they are used to achieve such benefits [22]. Current gaps and challenges for S&OP research include the following:  
* Gap 1--The integrated S&OP system approach: This approach focuses on how the S&OP process is part of an integrated planning system in which S&OP is one step in a hierarchy that transforms strategic planning into operational plans. Hence, these kinds of studies are absent in current S&OP research. Therefore, the association of S&OP with risk management is a key area for S&OP studies [22]. As a result, this gap seeks to develop holistic approaches to integrate the balance of demand and supply with strategic planning [23], as well as to develop operational measures and measurement approaches to operationally assess S&OP performance [22]. * Gap 2--S&OP in specific environments [22]:  
* Industry: S&OP analysis across industries. * Organizational: Impact of organizational characteristics on S&OP. * Complexity: S&OP must handle different complex scenarios to manage dynamic supply chain complexity with such variations and uncertainty using, for example, scenario planning, which is a key capability of S&OP. * Gap 3--Supply chain collaboration and marketing role: Less than 15% of papers related to supply-demand balancing are published in academic journals. In addition, in the marketing field, there are few S&OP studies. Considering the fundamental role that marketing and sales have in the demand side of the S&OP process, this lack of research studies in the field creates an opportunity. Therefore, this gap seeks future S&OP research to optimize supply chain collaboration, for which purpose marketing has a key role to play [23]. * Gap 4--Anticipate the effect of factors on demand: When performing S&OP for a supply chain, the producer must be able to identify and anticipate the effects on demand when a change in a factor, such as sales promotions, takes place. Studies in this area seek to estimate how and why demand will change over the planning horizon, depending on various factors [24]. * Gap 5--Big data and predictive analytics: Research in this area can enhance S&OP capabilities [25]. In addition, this area seeks to develop sales forecasting management as an organizational capability [26]. As a result of the abovementioned challenges and gaps, the aim of this research is to propose an integrated S&OP methodology to support managers and planning employees in their decision-making processes when performing their sales and operations plans and functions. For this reason, several novelties are applied to the model. The scope of the research includes manufacturing and assembly organizations in the three planning horizons of short-, medium-, and long-term, up to several years. In addition, the model is applied to the automotive industry, using system dynamics to compare the integrated predictive S&OP methodology developed with a classical S&OP approach. Both approaches are compared based on parameters such as work-in-progress (WIP) stock, customer order lead time, on-time-to-delivery (OTD), and capacity utilization. On this basis, there are various potential demand scenarios to be applied in the supply chain of supplier, producer, and distributor. By simulating different scenarios, the goal of testing the model to verify the hypothesis is realized.