The property of being effective, of achieving results.The effectiveness of the drug was well established.
The capacity or potential for achieving results.
What Happened to the Rule of Law?
The degree to which something achieves results.He questioned the effectiveness of the treatment.
2013, Phil McNulty, "http://www.bbc.co.uk/sport/0/football/23830980", BBC Sport, 1 September 2013:United were having more possession but a sign of the effectiveness of Liverpool's defence was that it took the visitors 76 minutes to force Mignolet into serious action, when he dived to punch away a shot from substitute Nani.
