Tip # 4 – Review The Correlation Chart
Investopedia defines “correlation” as a statistic that measures the degree to which two securities move in relation to each other. Correlations are used in advanced portfolio management. Correlation is computed into what is known as the correlation coefficient, which has value that must fall between -1 and 1.
A perfect positive correlation means that the correlation coefficient is exactly 1. This implies that as one security moves, either up or down, the other security moves in lockstep, in the same direction. A perfect negative correlation means that two assets move in opposite directions, while a zero correlation implies no relationship at all.
But note that correlation is not causation – ie rising ice cream sales does not necessarily increase the number of shark attacks (see figure below).