We used a scale. I attach our paper:

Dear Prem Knowles

Thanks for asking this important question and many thanks to S. Béatrice Marianne Ewalds-Kvist for your valuable answer. In fact I was also searching for the same which I got now.

Regards,

Nandan

It is called the Emotional Quotient Inventory. A key article may be found here on ResearchGate (see link below). Reuven Bar-On is on ResearchGate himself, so why not try contacting him directly? Or, of course, contact the publishers of the test (see link below)? Note: It is not a "free" test. There may be free options, probably not as strong psychometrically and without as much validity information. But if you are conducting academic research, the publishers may offer a steep discount.

Article The Bar-On Model of Emotional-Social Intelligence

https://www.hpsys.com/EI_BarOnEQ-I.htm