"Scientists (and others) often arrive at a point where they assume, pragmatically, that there is a causal link between two things even when the link can’t be explained in a coherent model. In fact, this happens quite often and is probably what directs a lot of research, as novel experiments or exploratory programs are designed to pin down such a model. When this happens, the presumption of causality has been derived from mere correlation. It has been said (go look it up in Wikipedia) that correlation does not prove causation, but it can be a hint. In practice, and logically, there is too large a gap between the statement 'Correlation implies or proves causality' and 'Correlation is a hint.'"
http://scienceblogs.com/gregladen/2011/0...elation-i/
"Researchers trying to find reasons for various things will often use statistical methods to establish correlations: this may be the first step toward establishing the cause. Scientists and statisticians can use a formula to determine the strength of a relationship between two phenomena. This gives a figure, known as the square of the correlation coefficient, or R2, which always lies between 0 and 1, with a value closer to 1 indicating a stronger correlation."
http://www.wisegeek.org/what-is-the-diff...lation.htm
"Correlations can be positive - so that as one variable (marijuana smoking) goes up, so does the other (relationship trouble); or they can be negative, which would mean that as one variable goes up (methamphetamine smoking) another goes down (grade point average). The trouble is that, unless they are properly controlled for, there could be other variables affecting this relationship that the researchers don't know about. For instance, education, gender, and mental health issues could be behind the marijuana-relationship association (these variables were all controlled for by the researchers in that study)."
http://www.psychologytoday.com/blog/all-...t-all-mean
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http://scienceblogs.com/gregladen/2011/0...elation-i/
"Researchers trying to find reasons for various things will often use statistical methods to establish correlations: this may be the first step toward establishing the cause. Scientists and statisticians can use a formula to determine the strength of a relationship between two phenomena. This gives a figure, known as the square of the correlation coefficient, or R2, which always lies between 0 and 1, with a value closer to 1 indicating a stronger correlation."
http://www.wisegeek.org/what-is-the-diff...lation.htm
"Correlations can be positive - so that as one variable (marijuana smoking) goes up, so does the other (relationship trouble); or they can be negative, which would mean that as one variable goes up (methamphetamine smoking) another goes down (grade point average). The trouble is that, unless they are properly controlled for, there could be other variables affecting this relationship that the researchers don't know about. For instance, education, gender, and mental health issues could be behind the marijuana-relationship association (these variables were all controlled for by the researchers in that study)."
http://www.psychologytoday.com/blog/all-...t-all-mean
Want to know anything else about this?
