→Causation versus correlation: superfical counterexamples
===Independent shifts of the demand curve===
To understand how the causation and correlation issue can be confused, consider a shift in the demand curve due to a change in one of the other [[determinants of demand]] (i.e., an [[exogenous parameter]] in the interaction between demand and price). If the shift is outward (also called an ''expansion'' of the demand curve), i.e., if demand increases for every given price, this causes a tendency for the [[market price]] (the price at which the market clears) to rise. Similarly, if the shift is inward (also called a ''contraction'' of the demand curve), there is a tendency for the market price to fall.