An index used to monitor inflation. The Employment Cost Index measures the relative changes in wages, benefits, and bonuses for a specific group of occupations. The reason the ECI is thought to be an indicator of inflation is that as wages increase, the added cost is often passed to consumers shortly thereafter in the form of higher prices (which is inflation). In combination with the productivity report, the ECI can reveal whether the increased cost of labor is justified or not. The ECI is released at 8:30 am EST on the last Thursday of January, April, July, and November.