Demand
These following conditions cause demand to fall and shift leftwards:
- Low prices of substitute goods (goods that perform the same function as each other and can be used as substitutes for one another, for example, a computer and a laptop). If substitute goods are cheaper, then demand for the original good will fall because consumers are buying the substitutes (assuming everything else remains constant – ceteris paribus).
- High prices of complementary goods (goods that are bought with each other, for example a printer and printer ink). If complementary goods are sold at high prices, consumers may decide the purchase is not worth it, ceteris paribus.
- Low personal income. This leads the household with lower disposable income for spending, therefore demand for goods and services may fall.
- Tastes and preferences for the good changes.
The reverse of these factors will cause demand to rise and shift rightwards.
Supply
The following factors cause (short run) supply to fall and shift leftwards:
- High costs of production
- Wage costs
- Rent prices
- Commodity/raw material costs
- Cost of borrowing (higher interest rates)
- Higher taxes
- Corporation tax
- VAT
- Excise duties
- Lack of subsidies/grants
These factors can cause firms to leave the market, thus resulting in a fall of supply.
The opposite of the factors above can cause supply to increase and shift rightwards, along with the addition of technical progress.
