Sunoco is readying a chain-wide set of marketing initiatives designed to improve its image with women drivers and win more return business to its service station outlets throughout Ontario. It refurbished all of its restrooms and tried to hire friendly personalities and real customer service skills instead of "just who was available". It hired an outside research organization to send people to Sunoco service stations twice monthly to grade staff on their customer interaction skills. What research method did Sunoco use to make sure that each station was implementing the new service strategy?