The Customer Effort Score, or CES, is a key indicator of customer experience, introduced in the Harvard Business Review in 2010. It is based on a question asked of customers after a purchase, a service used, or contact with customer service. This question, worded differently depending on the action, aims to assess the effort expended by the customer on a scale of 1 to X. Initially rated from 1 to 5, CES 2.0 has been redesigned to provide a score calculated similarly to the Net Promoter Score (NPS).

Unlike the NPS, which measures satisfaction, the CES evaluates the overall effort exerted by the customer. According to its creators, it proves to be a more reliable indicator of loyalty, based on a study of 70,000 respondents. Rather than trying to attract customers, it is recommended to reduce their effort, according to the logic of the CES. However, the predictive power of CES compared to NPS remains debated, especially after customer interactions. Effort expended does not always guarantee satisfaction, as in some cases, effort may be unavoidable.

CES, expressed as an overall score, is better suited to measuring the effort required in specific processes, such as online payment or searching for information on a website. Conversely, it is less effective for evaluating more complex processes, such as online purchasing. Therefore, it is recommended to measure CES at key stages of the customer relationship, considering it as a complement rather than an alternative to NPS, which is particularly useful for tracking trends through a barometer.

Comparing CES scores between different companies can be of limited relevance, as its interpretation varies depending on the context. In the field of after-sales service, for example at the retailer BUT, CES is