Use of AI is based on self-reported data. From the paper:

> The respondents to the interviews are senior managers or financial directors with responsibility for investment decisions and how investments are financed – for example, the owner, chief financial officer or chief executive officer

> Firms are asked the following question: “To what extent, if at all, are big data analytics and artificial intelligence used within your business? A. Not used in the business. B. Used in parts of the business. C. Entire business is organized around this technology.”

AI adoption is defined as the manager answering B or C.

I'm doubtful that this data is going to be very robust. Some senior tech managers are very keen to talk about AI, while at the same time knowing little about how much AI is actually being used by workers. At other companies you'll have people using free or personal ChatGPT accounts without the knowledge of management.

Also "big data" is not exactly AI.

The productivity information is robust as it's based on company accounts, albeit from 2024 so a couple of years out of date now.