## 1 Introduction
### Classification of Challenges  
The barriers and issues hindering the appropriate implementation and execution of servitization are based on variety of grounds. Several authors elaborate this topic, ultimately revealing related results. Accordingly, the extensive literature review of [50; 51] identified five characteristics consisting of (i) organizational culture, (ii) pricing, (iii) risk absorption, (iv) complicated customer demand, and (v) close cooperation. Additionally, several other researchers retrieved characteristics of servitization challenges by conducting case studies or interviews. There are also classifications of challenges regarding servitization manifested by marketing-, production-, delivery-, product-design-, communication- and relationship-challenges [13; 40] as well as embedded product-service culture, delivery of integrated offering, internal processes and capabilities, strategic alignment and supplier relationships [35; 52].  
In order to provide a valid framework to systematize barriers and challenges, we suggest a classification to consolidate related findings. Based on [34; 53], who derived a basic organizational structure for servitizing companies consisting of front-end customer-facing units and back-end units separated into product- and service-units, we make a distinction of barriers and challenges according to their appearance manifested by front-end and back-end activities. Table 1 illustrates the corresponding allocation of barriers among front-end and back-end activities.  
Table 1 reveals two confusions originating from the primary classification regarding the topic of relationships and delivery, since these terms are classified in diverging categories. According to [40; 54], the relationship challenge draws on a lack of credibility between customer and service provider, whereas [35; 36; 55] identified challenges regarding the relationship between the company and its supplier. Finally, [40; 42; 56] engaged on the delivery challenge concerning internal organizational and structural issues, whilst [35; 36; 57] considered challenges regarding diverging service/value offering perceptions. Thus, these comparisons affirm the suggested classification, which serves as a framework in Sections 2 and 3.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Approach** & **Front-End Activities** & **Back-End Activities** \\ \hline \multirow{3}{*}{[51]} & Pricing & \multirow{3}{*}{Organizational Culture} \\  & Risk Absorption & \\  & Complicated Customer Demand & \\ \hline \multirow{3}{*}{[40; 42]} & Marketing Challenge & \multirow{3}{*}{Production Challenge} \\  & Product-Design Challenge & \\ \cline{1-1}  & Communication Challenge & \\ \cline{1-1}  & Relationship Challenge & \\ \hline \multirow{3}{*}{[35; 36]} & Delivery of integrated offering & \multirow{3}{*}{Embedded P-S Culture} \\  & Strategic Alignment & \\ \cline{1-1}  & & \\ \cline{1-1} \cline{3-3} \cline{3-3} \cline{3-3} \cline{3-3} \cline{3-3} \cline{3-3} \cline{3-3} \cline{3-3} \cline{3-3} \cline{3-3} \cline{3-3} \cline{3-3} \cline{3-3} \cline{3-3} \cline{3-3} \cline{3-3} \cline{3-3} & \\ \cline{1-1}  & & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Various Approaches on Challenges in the Context of Front-End and Back-End Activities.