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PROSET – Productivity Increase by Service Experience Management

For many businesses, cross- and up-selling are among the most important objectives in customer management.When a customer calls a business, it seems to be the perfect time for cross- or up-selling activities.

  • May any incoming call therefore equally be seen as potential for cross- and up-selling?
  • And may cross- and up-selling also be successful if the customer has actually called in order to complain?
  • Does success depend on how long the customer had to wait in the loop? 

PROSET – The research project

In order to obtain answers to these questions, the Munich TU, in cooperation with b.telligent, researches the most important success factors for cross- and up-selling in case of inbound call center calls within the scope of the customer intelligence study PROSET.

The research project is conducted by the chair of Technical Services and Operations Management, headed by Professor Dr. Rainer Kolisch, and the chair of Technology Marketing (Professor Dr. Florian v. Wagenheim) at the ETH Zurich. The project is supported by the Federal Ministry of Education and Research (Bundesministerium für Bildung und Forschung), the project management organization in the DLR (German Aerospace Center) and the strategic partnership “Productivity of Services”. The anticipated project end is in February 2014.

Objectives and expected results

There is substantial potential in the customer initiated dialogue (“Customer-initiated Contacts“, CICs) with the business. The main difference between this kind of customer contact and outbound campaigns is that the customer actively indicates his/her interest in the business by his/her inquiry and determines the time and channel of the first contact himself/herself. This is a considerable difference to outbound campaigns – the frequency and timing of which frequently annoy the customers. While in case of classical outbound direct marketing campaigns, only low response rates of about 2.9 to 4.4 % (DMA 2009) are measured in telemarketing, the CICs are characterized by significantly higher response rates – according to Gardner up to 15 times higher. The question is, however, what determines the success of cross- and up- selling in this context.

Among others, the following questions are reviewed in the course of the project:

  • Does the general level of satisfaction positively influence the purchasing behavior?
  • Does the customer’s concern affect the success of cross- and up-selling?
  • Does the long waiting time of the customer affect his/her willingness to purchase at a later stage?
  • Is the customer still open to the agent’s offers after a long conversation?
  • At what times of day are more products sold?
  • Does the calling source (mobile/landline) chosen by the customer affect the success of cross- and up-selling?  
  • Do customers with lower customer lifetime value (CLTV) purchase more often than customers with high CLTV?

The study tries to answer these questions by means of the data of a mobile communication service provider. The telecommunications industry is known both for large data volumes and for the diversity of data sources and data types. The customer service plays a significant role in this industry and call centers are thus a particularly important contact point for the customer.  





Customer satisfaction is an important, even though not necessarily easily measurable key indicator. Of course, the question whether the satisfaction with the telephone call is also a key factor for the success of cross- and up- selling is raised in this context.

The analysis shows that satisfaction has a statistically significant influence on the sales success. Customers who were very pleased with the telephone call (9 or 10 of 10 points) have a higher purchase likelihood than customers who awarded lower marks.

Concern – Complaint/Information/Invoice

Previous research has shown that there is a higher likelihood for the purchase of additional or higher-quality products or services if the reason for the call is a need for information. In contrast, the likelihood is not higher in case of a question concerning the invoice. The study is designed to review whether a more refined classification of the categories of calls leads to a better understanding.

The interim results of the study show that the concern has a statistically significant influence on the purchase behavior. The results for calls with questions concerning the operation of devices, device functions or an update are of particular interest. Here, a positive correlation with cross- and up-selling is expected.

Waiting Time/Talking Time

Here, it is important to define what a “long waiting time” actually is. In case of a good service level, no influence on the purchasing success is expected. However, every agent and call center manager wonders: should one try to offer the customer more products or services after a long conversation? Research answers this question: the waiting time has no influence on the purchasing behavior. The talking time also does not affect the success of cross- and up-selling.

Daytime and Source of the Call (Mobile/Landline)

The customer himself/herself chooses the time at which he/she contacts the supplier. Thus, it seems plausible that it is a point of time when the customer has enough time to have a talk. As in the case of time, the customer also decides himself/herself whether to place the call from a landline or a mobile phone. The initial analysis results indicate a very slight influence of time and source of the call on the success of cross- and up- selling. Times between 7 p.m. and 9 p.m. and calls made from the own mobile net seem beneficial for the sales success.

Customer Lifetime Value

CLTV is becoming increasingly important as a key indicator in both business and economics. Many businesses concentrate on the determination of their most profitable customers and the fostering of long-term relationships. CLTV stands for the profit margin which a customer contributes during his/her customer life cycle, discounted to the observation date. But how do customers with various CLTVs differ from one another? Are customers with a lower CLTV possibly more receptive to new products? The interim research results show that customers with a high CLTV tend to be more willing to buy than customers with a lower CLTV.  


The objective of the study is to identify success factors for cross- and up-selling in case of inbound call center calls and to develop recommendations for action to improve service experiences on this basis.  

The questions were developed in cooperation with both the marketing department and call center managers and agents which once again reveals the relevance for both areas.   

The full results of the study can be looked up in the paper of Sonja Heins, Success factors in cross- and upselling — utilizing incoming calls at customer service centers.

Laurentius Malter
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Laurentius Malter
Competence Center Manager
Laurentius is passionate about his specialism, which is customer engagement & martech. One thing is for sure: marketing and customer experience are becoming more and more digital and thus more and more technical. Companies who deploy marketing automation and the right data management tools are able to enhance their digital interaction with customers and stay one step ahead of their competition.
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