Here are a few of the stats from studies I could find on topics related to Service Design:

The value of good service

1. 83% of consumers cite good customer service as the most important factor—outside of price and product—when deciding what to buy. (Khoros)
2. 75% of customers are willing to spend more to buy from businesses that give them a good customer experience. (Zendesk)
3. 82% of customers will spend more money on companies that deliver great online service. (Gladly)
4. A mere 5% increase in customer retention produces more than a 25% increase in profits. (Bain & Company)
5. Consumers are 3.5 times more likely to purchase more from a brand after a positive customer experience (XM Institute 2021)
6. Customer experience-focused businesses have a 1.5x higher year on year growth than other companies in customer retention, repeat purchase rates, and customer lifetime value (Adobe 2018)
7. An NPS® promoter score has a customer lifetime value that's 600% - 1400% higher than a detractor. (HubSpot Research)

Good services and recommendation

• If provided with great service, 62% of customers will recommend a brand to a friend. (Gladly)
• A good customer service experience heavily impacts recommendations. 94% of consumers who give a company a “very good” CX rating are likely to recommend that company. (Qualtrics XM Institute)

The state of the service industry

1. More than 65% of people have higher expectations for customer service today than they did three to five years ago. (Netomi)
2. Only 19% of consumers believe customer service is exceeding expectations. (Gladly)

Personal services

1. 75% of consumers prefer an authentic human voice over a perfectly crafted brand message. (Khoros)
2. 53% of shoppers believe their feedback doesn't go to anyone who can actually act on it. (Microsoft)

Service problems and frustrations

1. 64% of consumers aren’t able to get help or solve their problem through their provider’s customer service. (Airkit)
2. 33% of customers are most frustrated by having to wait on hold. 33% are most frustrated by having to repeat themselves to multiple support reps. (HubSpot Research)
3. 50% of consumers will switch to a competitor after one bad experience, and 80% will switch to a competitor after more than one bad experience. (Zendesk)

Going further

To go further you can explore my bookmarks here.