Changes

'''Causal association is the presence or absence of a variable (e.g. [[smoking]]) is responsible for an increase or decrease in another variable (e.g. [[cancer]]). A change in exposure leads to a change in the outcome of interest.<ref>http://www.cdc.gov/vaccines/about/terms/glossary.htm#c</ref>

'''Causal association''' is the presence or absence of a variable (e.g. [[smoking]]) is responsible for an increase or decrease in another variable (e.g. [[cancer]]). A change in exposure leads to a change in the outcome of interest.<ref>http://www.cdc.gov/vaccines/about/terms/glossary.htm#c</ref>

==References==

==References==