Results for RQ2

For RQ2, the sampled papers were reviewed to distinguish papers with performance indicators from papers without performance indicators. A further distinction was made between indicators found with operationalization (i.e., concretization by means of a question or formula) and those without operationalization. We note that for many indicators, no operationalization was available. We discovered that only 30 of the 76 sampled papers contained some type of performance indicator (namely 3, 5, 6, 7, 11, 16, 17, 18, 20, 22, 26, 27, 30, 35, 37, 40, 43, 46, 49, 51, 52, 53, 55, 57, 58, 59, 60, 66, 71, 73). In total, approximately 380 individual indicators were found throughout all the sampled papers (including duplicates), which were combined based on similarities and modified to use more generic terms. This resulted in 87 indicators with operationalization  and 48 indicators without operationalization.

The 87 indicators with operationalization were then categorized according to the four perspectives of the BSC (i.e., financial, customer, business processes, and "learning and growth") and the four established dimensions of process performance (i.e., time, cost, quality, and flexibility). In particular, based in the identified indicators, we revealed 11 sub-perspectives within the initial BSC perspectives to better emphasize the focus of the indicators and the different target groups (Table 5): (1) financial performance for shareholders and top management, (2) customer-related performance, (3) supplier-related performance, (4) society-related performance, (5) general process performance, (6) time-related process performance, (7) cost-related process performance, (8) process performance related to internal quality, (9) flexibility-related process performance, (10) (digital) innovation performance, and (11) employee-related performance.

Table 5 A description of the observed performance perspectives, linked to the Balanced scorecard (Kaplan and Norton 1996, 2001)

Initial BSC perspectives Observed perspectives based on target groups and focus Scope of the performance indicators
1. Financial performance 1.1 Financial performance for shareholders and top management Strategic financial data
2. Customer-related performance 2.1 Customer performance Outcomes of external quality or meeting end user needs
2.2 Supplier performance External collaboration and process dependencies
2.3 Society performance Outcomes for other stakeholders and the environment during process work
3. Internal business process performance 3.1 General process performance Descriptive data of process work, not related to time, costs, quality or flexibility
3.2 Time-related process performance Time-related data of process work
3.3 Cost-related process performance Operational financial data
3.4 Process performance related to internal quality Capability of meeting end user needs and internal user needs
3.5 Flexibility-related process performance Data of changes or variants in process work
4. Performance related to “learning and growth” 4.1 (Digital) innovation performance Innovation of processes and innovation projects
4.2 Employee performance Staff contributions to process work and personal development

For reasons of objectivity, the observed performance indicators were assigned to a single perspective starting from recognized frameworks. Bias was further reduced by following the definitions of Table 5. Furthermore, the authors of this article first classified the indicators individually and then reached consensus to obtain a more objective categorization.

Additional rationale for the identification of 11 performance perspectives is presented in Table 6, which compares our observations with the perspectives adopted by the most commonly used performance measurement models (see "Theoretical background" section). This comparison allows us to highlight similarities and differences with other respected models. In particular, Table 6 shows that we did not observe a dedicated perspective for strategy and that we did not differentiate between financial indicators and market indicators. Nonetheless, the similarities in Table 6 prevail. For instance, Cross and Lynch also acknowledge different process dimensions. Further, Kueng and the EFQM also differentiate employee performance from innovation performance, and they both add a separate perspective for results related to the entire society.

Table 6 The comparison of our observed performance perspectives with the perspectives taken in the most commonly used performance measurement models in the literature

Balanced scorecard
EFQM
Kueng
Cross and Lynch
Our observed performance perspectives
Financial perspective Key results Financial view Financial measures
Market measures 		Financial performance for shareholders and top management
Customer perspective Customer results Customer view Customer satisfaction Customer performance
Supplier performance
Society performance
Internal business processes perspective Enablers (processes/products/services, people, strategy, partnerships/resources, leadership) Overall process performance based on the other views as driving forces Flexibility
Productivity
Quality
Delivery
Process time
Cost 		General process performance
Time-related process performance
Cost-related process performance
Process performance related to internal quality
Flexibility-related process performance
“Learning and growth” perspective People results
Learning, creativity and innovation 		Employee view
Innovation view 		– (Digital) innovation performance
Employee performance
– Society results Societal view – Society performance as a sub-perspective of customer performance 

Figure 10 summarizes the number of performance indicators that we identified in the process literature per observed performance perspective. Not surprisingly, the initial BSC perspective of internal business process performance contains most of the performance indicators: 29 of 87 indicators. However, the other initial BSC perspectives are also covered by a relatively high number of indicators: 16 indicators for both financial performance and customer-related performance and 26 indicators for "learning and growth". This result confirms the close link between process performance and organizational performance, as mentioned in the introduction.

Fig. 10 The number of performance indicators with operationalization per performance perspective

Fig. 10 The number of performance indicators with operationalization per performance perspective

A more detailed comparison of the perspectives provides interesting refinements to the state of the research. More specifically, Fig. 10 shows that five performance perspectives have more than ten indicators in the sample, indicating that academic research focuses more on financial performance for shareholders and top management and performance related to customers, process time, innovation and employees. On the other hand, fewer than five performance indicators were found in the sample for the perspectives related to suppliers, society, process costs and process flexibility, indicating that the literature focuses less on those perspectives. The latter remains largely overlooked by academic research, possibly due to the newly emerging character of these perspectives.

We must, however, note that the majority of the performance indicators are mentioned in only a few papers. For instance, 59 of the 87 indicators were cited in a single paper, whereas the remainder are mentioned in more than one paper. Eleven performance indicators are frequently mentioned in the process literature (i.e., by five or more papers). These indicators include four indicators of customer-related performance (i.e., customer complaints, perceived customer satisfaction, query time, and delivery reliability), three indicators of time-related process performance (i.e., process cycle time, sub-process turnaround time, and process waiting time), one cost-related performance indicator (i.e., process cost), two indicators of process performance related to internal quality (i.e., quality of internal outputs and deadline adherence), and one indicator of employee performance (i.e., perceived employee satisfaction).

Consistent with "Performance indicators" section, the different performance perspectives are a combination of financial or cost-related indicators with non-financial data. The latter also take the upper hand in our sample. Furthermore, the sample includes a combination of objective and subjective indicators, and the vast majority are objective indicators. Only eight indicators explicitly refer to qualitative scales; for instance, to measure the degree of satisfaction of the different stakeholder groups. For all the other performance indicators, a quantifiable alternative is provided.

It is important to remember that a distinction was made between the indicators with operationalization and those without operationalization. The list of 87 performance indicators, as given in "Appendix 3", can thus be extended with those indicators for which operationalization is missing in the reviewed literature. Specifically, we found 48 additional performance indicators that mainly address supplier performance, process performance related to costs and flexibility, and the employee-related aspects of digital innovation. Consequently, this structured literature review uncovered a total of 135 performance indicators that are directly or indirectly linked to business process performance.

Finally, the total list of 135 performance indicators was evaluated for its comprehensiveness by comparing the identified indicators with other BSC variants that were not included in our sample. More specifically, based on a random search, we looked for two BSC variants in the Web of Science that did not fit the search strategy of this structured literature review: one that did not fit the search term of "business process*" and another that did not fit any of the performance-related search terms of "performance indicator*", "performance metric*" or "performance measur*". These two BSC variants cover 30 and 17 performance indicators, respectively, and are thus less comprehensive than the extended list presented in this study. Most of the performance indicators suggested by the two BSC variants are either directly covered in our findings or could be derived after recalculations. Only five performance indicators could not be linked to our list of 135 indicators, and these suggest possible refinements regarding (1) the growth potential of employees, (2) new markets, (3) the social performance of suppliers, (4) philanthropy, or (5) industry-specific events.