"Initiation rates" refers to the speed or frequency at which something begins or starts. It shows how fast or often a particular process or action is being initiated. Full definition
Support is likely to be more effective in settings with high initiation rates. (cochranelibrary-wiley.com)
To determine factors influencing feeding decisions, breastfeeding and / or bottle initiation rates, as well as breastfeeding duration. (pediatrics.aappublications.org)
My generation had a breastfeeding initiation rate under 30 %. (skepticalob.com)