Income elasticity of demand — Edexcel A-Level Business
Test yourself on Income elasticity of demand with PEARSON EDEXCEL A-Level practice questions.
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Income elasticity of demand explained
The measure is the percentage change in quantity demanded divided by the percentage change in real incomes, a pure ratio with no units, and the order of that division is the half students reverse.
Read the full explanation
Work each percentage from its own starting value: if sales of a premium ready meal rise by six per cent in a year when real disposable income rises by three per cent, the answer is positive two and the product is strongly income sensitive. Use real income rather than the cash figure, because inflation can turn a nominal pay rise into a fall in purchasing power and flip the sign. The result matters for forecasting, since a firm with a high positive reading should plan capacity for a boom and cash reserves for a downturn.
b) Interpretation of numerical values of income elasticity of demand
The sign sorts the product and the size sorts the risk. A positive reading marks a normal good, and one above positive one marks a luxury whose sales swing harder than the economy does; between zero and positive one sits a necessity that drifts up slowly with prosperity; a negative reading marks an inferior good whose sales rise as incomes fall. Own label value ranges and the discount grocers behaved exactly that way through the recession that followed the financial crisis, while restaurant meals and new cars fell away. For a business the reading is a warning about the cycle, because a portfolio weighted towards strongly positive products earns well in a boom and needs cash and flexible capacity to survive a contraction.
c) The factors influencing income elasticity of demand
Whether sales swing with the economy comes down to how easily a purchase can be postponed or traded down. Something bought out of necessity, bread or a bus fare, barely moves; something that can wait a year, a kitchen or a holiday, moves a great deal; and where a cheaper version of the same thing exists, spending shifts towards it rather than disappearing, which is why discount ranges grow as incomes fall. Positioning is therefore a business choice and not a fact of nature, since a brand sold on status will swing harder than one sold on value. Living standards also reset the categories over time, as air travel and smartphones have moved from luxury towards near necessity within a generation, so an old reading can mislead.
d) The significance of income elasticity of demand to businesses
The reading turns a macroeconomic forecast into a sales forecast, which makes it a planning tool rather than a statistic: multiply the expected change in real incomes by the coefficient and the firm has a volume estimate to set capacity, recruitment and cash against. It also shapes the portfolio, because a range spread across positive and negative readings is a hedge, and it guides market entry, since a strongly income sensitive product belongs where incomes are growing fastest. Diversification in the sense Ansoff used the word is often defended on exactly this ground. What the figure is blind to is everything else moving at once, since a rival's price cut, a shift in taste or a credit squeeze can swamp the income effect, and the forecast underneath it may simply be wrong.
Your focus
- a) Calculation of income elasticity of demand
- b) Interpretation of numerical values of income elasticity of demand
- c) The factors influencing income elasticity of demand
Show all 4 objectives
- d) The significance of income elasticity of demand to businesses
Income elasticity of demand exam tips
Marking Points
- Divides the percentage change in quantity by the percentage change in real income, in that order, and shows both percentages before dividing
- Keeps the sign, since a negative result identifies an inferior good and is not an arithmetic slip to be tidied away
- Uses real rather than nominal income wherever the extract supplies an inflation figure
- Rounds consistently, states the coefficient to a stated number of decimal places and then explains it in one sentence
- Classifies from the sign first, normal against inferior, before commenting on the size of the figure
- Uses positive one as the dividing line between a necessity and a luxury and places the case product on the correct side of it
- Turns the reading into a forecast, for example a fall of two per cent in real incomes against a coefficient of positive three giving a fall of six per cent in volume
- Links the reading to a decision, such as widening the range or building cash reserves ahead of a downturn
- Explains a determinant through the ability to postpone or trade down, rather than simply labelling the product a luxury
- Connects that determinant to where the case firm has positioned itself, using its price point and brand evidence from the extract
- Recognises that the reading changes over time as incomes and tastes shift, so a historic figure needs treating with care
- Contrasts two products in the same market to show why their readings differ
- Combines the coefficient with a forecast income change to produce an estimated change in volume or revenue, and then acts on that number
- Applies it to a real decision such as capacity, recruitment, stock levels or cash reserves rather than leaving it as a classification
- Argues the hedging case for holding products with opposite signs inside one portfolio
- Evaluates by naming what the coefficient holds constant and how reliable the underlying income forecast is
Examiner Tips
- 💡These calculations carry method marks, so write the ratio out in words before substituting the figures
- 💡Show the two percentage changes as a step of their own, because one method mark is normally for converting the raw figures into percentages
- 💡Data response items give coefficients for several products in a table and ask which the firm should push in a downturn, so rank them by sign and then by size before writing
- 💡Judgement marks come from the limits of the figure, so question whether the estimate holds when incomes fall sharply rather than drift
- 💡Questions pair this with a macroeconomic extract on growth or a squeeze on real wages, so quote that figure and then reason about the product
- 💡Two developed determinants with case evidence beat five named ones, and the second is where the analysis marks are awarded
- 💡This is the twelve or twenty mark evaluation on a named firm, so run the argument from forecast to decision and then to the conditions that would overturn it
- 💡Bring price sensitivity in as a counterweight, because a strong income effect can be cancelled by a competitor's discount
Common Mistakes
- Dividing the income change by the quantity change, which inverts the reading and turns a sensitive product into an insensitive one
- Using the absolute change in units or pounds instead of the percentage change, so the answer has no comparable scale
- Ignoring an inflation figure printed in the extract and working from the cash income change instead
- Calling a negative reading an error and stripping the minus sign, which hides the one finding that matters in a recession
- Confusing income sensitivity with price sensitivity and reading the figure as a response to a price change
- Describing a product as a luxury because it is expensive rather than because its reading exceeds positive one
- Reciting the determinants of price sensitivity, especially substitutes at the same price, without adapting them to income
- Assuming the firm has no control over its own reading, when positioning, range width and entry price all move it
- Treating consumer confidence as the same thing as income, when spending can fall while incomes hold up
- Stopping at labelling the product normal or inferior without saying what the firm should now do differently
- Trusting one coefficient for a whole business when different ranges inside it behave in opposite directions
- Forgetting that the income forecast is itself uncertain, so the sales estimate inherits that uncertainty