Differentiate between movement along and shift of the demand curve.

Movement along the demand curve represents a change in quantity demanded due to price changes, while a shift of the demand curve indicates a change in demand due to non-price factors.

Movement along the demand curve, also known as a change in quantity demanded, is caused by a change in the price of the good or service itself. When the price of a good increases, the quantity demanded decreases, causing a movement up along the demand curve. Conversely, when the price decreases, the quantity demanded increases, resulting in a movement down the demand curve. This movement is a reflection of the law of demand, which states that there is an inverse relationship between price and quantity demanded, ceteris paribus (all other things being equal).

On the other hand, a shift in the demand curve represents a change in demand due to factors other than the price of the good or service. These factors can include changes in income, tastes and preferences, the price of related goods (substitutes or complements), expectations of future prices, and the number of potential buyers. For instance, an increase in income would typically shift the demand curve to the right, indicating an increase in demand at each price level. Conversely, a decrease in income would shift the demand curve to the left, indicating a decrease in demand at each price level.

It's important to note that a movement along the demand curve only involves one variable - the price of the good or service in question. However, a shift of the demand curve involves changes in other variables that affect demand. Therefore, while a movement along the demand curve results in a new quantity demanded, a shift of the demand curve results in a new demand curve altogether.

In summary, while both movement along and shift of the demand curve relate to changes in demand, they are caused by different factors and have different implications. Understanding the distinction between the two is crucial for analysing changes in the market.