Full Idea
In Mill's 'Method of Agreement' the cause is the common factor in a number of otherwise different cases in which the effect occurs.
Gist of Idea
In Mill's 'Method of Agreement' cause is the common factor in a range of different cases
Source
report of John Stuart Mill (System of Logic [1843], p.255) by Stathis Psillos - Causation and Explanation §2.3
Book Reference
Psillos,Stathis: 'Causation and Explanation' [Acumen 2002], p.63
A Reaction
This looks more likely to be good evidence for the cause of an event, rather than a definition of what a cause actually is. Suppose a footballer only scores if and only if I go to watch him?