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IB DP Economics Study Notes

2.1.3 Non-Price Determinants of Demand

Understanding the factors that influence demand is paramount for any economist. Beyond price, several non-price determinants can significantly shift the demand curve. This section will explore three primary non-price determinants: income, tastes and preferences, and the price of related goods.


Income is a fundamental determinant of demand. As consumers' income fluctuates, their capacity and propensity to purchase goods and services evolve. To understand how different income levels affect demand for goods differently, one can look into the Income Elasticity of Demand (YED), which measures the responsiveness of demand to a change in income.

Normal Goods

  • Definition: Goods for which demand rises with an increase in income and falls with a decrease in income.
  • Example: Luxury cars, high-end electronics, gourmet meals, and designer clothing.
  • Explanation: As people's financial situation improves, they often upgrade their lifestyle. They might move from budget-friendly options to premium ones, reflecting their increased purchasing power. On the other hand, during economic recessions or personal financial hardships, consumers might cut back on these goods first, as they are often seen as non-essential.

Inferior Goods

  • Definition: Goods for which demand falls as income rises and rises as income falls.
  • Example: Second-hand clothing, instant noodles, public transportation, and budget supermarkets.
  • Explanation: These goods often serve as alternatives to more expensive options. When consumers face financial constraints, they might opt for these to save money. However, as their income rises, they often revert to higher-quality or branded alternatives, reducing their reliance on inferior goods.
A graph illustrating the relationship between income and quantity demanded of different goods

Image courtesy of economicsonline

Tastes and Preferences

Tastes and preferences are dynamic and can significantly influence the demand for goods and services. They are moulded by various factors, including cultural, social, and individual influences. Cultural shifts towards sustainability highlight the externalities and welfare loss associated with consumption and production, impacting consumer preferences.

Cultural Influence

  • Explanation: Societal values, traditions, and norms can dictate the popularity of certain products. As societies evolve, so do their preferences.
  • Example: The global shift towards sustainability has led to an increased demand for organic foods, electric vehicles, and biodegradable products.
  • Impact: Companies often need to adapt their product lines to cater to these changing cultural preferences to remain relevant and competitive.

Social Influence

  • Explanation: Peer pressure, trends, and the influence of media and celebrities can cause sudden and sometimes short-lived spikes in demand.
  • Example: The rise of "athleisure" fashion, popularised by celebrities and influencers, led to a surge in demand for sporty yet casual clothing.
  • Impact: While such trends can offer businesses lucrative opportunities, they also pose risks, as the demand might wane as quickly as it rose.

Individual Factors

  • Explanation: Personal experiences, age, health, and significant life events can shape individual preferences.
  • Example: The birth of a child might increase a family's demand for baby products, larger vehicles, or bigger homes.
  • Impact: Businesses that can anticipate and cater to these individual life moments can capture significant market share. This is also why understanding government and market failures is crucial, as it can affect how these preferences are met in the market.
IB Economics Tutor Tip: Understand that shifts in demand due to non-price determinants, like income changes and evolving preferences, significantly impact market dynamics, requiring adaptive strategies for businesses and policymakers.

The interplay between products in the market is intricate. The demand for a particular product can be influenced by the price fluctuations of related goods. These goods can be broadly categorised into substitutes and complements, with their relationship further explored through the concept of Cross Elasticity of Demand (XED), which measures the sensitivity of demand for one good to a change in the price of another good.


  • Definition: Goods that can replace one another. A price increase in one can boost the demand for its substitute.
  • Example: Butter and margarine. If butter becomes more expensive due to supply constraints, consumers might switch to margarine.
  • Explanation: Substitutes have a positive cross-price elasticity of demand. This means that a price hike in one product can lead to an increased demand for its substitute. Businesses need to be aware of potential substitutes in the market, as they can affect their product's demand.


  • Definition: Goods that are typically consumed together. A price increase in one can dampen the demand for its complement.
  • Example: Computers and software. If computers become prohibitively expensive, the demand for software might also decline, as fewer people would be buying computers to run that software.
  • Explanation: Complements have a negative cross-price elasticity of demand. This means that a price increase in one product can lead to a decreased demand for its complement. Companies often bundle complementary products to boost sales.
Unknown block type "table", specify a component for it in the `components.types` option

A summary table of the determinants of demand.

IB Tutor Advice: For exams, practise applying these determinants to real-world scenarios, demonstrating your ability to analyse how they influence demand beyond mere theoretical understanding.

In conclusion, while price is a significant factor influencing demand, it's essential to recognise the role of non-price determinants. They can cause shifts in the demand curve, leading to changes in market equilibrium. For businesses, understanding these determinants is crucial for strategic planning and forecasting. For policymakers, it helps in crafting policies that can stabilise markets, promote growth, and ensure consumer welfare.


Technological advancements can significantly influence the non-price determinants of demand. They can introduce new products, rendering older ones obsolete, thereby shifting consumer preferences. For example, the advent of smartphones reduced the demand for traditional mobile phones and digital cameras. Technological advancements can also affect income levels. The rise of e-commerce platforms and remote working tools has created new income opportunities for many. Furthermore, technology can impact the price of related goods. Innovations in production processes can reduce costs, making certain goods cheaper and affecting the demand for their substitutes or complements.

Yes, certain goods, often termed as "necessities", tend to have a relatively stable demand regardless of changes in income. These are products or services that are essential for everyday life and don't see significant fluctuations in demand even when income levels change. Examples include basic food items like bread and rice, utilities like water and electricity, and essential medicines. While the demand for these goods might not be entirely inelastic to income changes, they are less sensitive compared to luxury or inferior goods. Even during economic downturns, consumers prioritise these essentials, ensuring a relatively consistent demand.

Absolutely. Government policies, especially those related to public health, safety, and environmental concerns, can shape tastes and preferences. For instance, public awareness campaigns about the health risks of smoking can reduce the demand for cigarettes. Similarly, policies promoting renewable energy sources can influence consumer preferences towards electric vehicles and away from petrol-based cars. Governments can also use subsidies, taxes, or regulations to make certain products more attractive or less appealing. For example, subsidising solar panels can increase their adoption, while imposing higher taxes on sugary drinks can deter their consumption. Through these mechanisms, governments can steer public preferences in directions that align with broader societal goals.

External events, such as global pandemics, can have profound effects on the non-price determinants of demand. Firstly, they can impact income levels. For instance, during a pandemic, widespread job losses or reduced working hours can decrease consumers' disposable income, affecting the demand for both normal and inferior goods. Secondly, such events can alter tastes and preferences. The COVID-19 pandemic, for example, led to a surge in demand for home fitness equipment and remote working tools due to lockdowns and a shift in work patterns. Lastly, the prices of related goods can also be affected. If a pandemic disrupts the supply chain for a product, its substitutes might see a rise in demand due to price or availability issues.

Advertisements and marketing campaigns play a pivotal role in shaping consumers' tastes and preferences. Through strategic messaging, imagery, and endorsements, they can create a perceived value or desirability for a product. For instance, a successful advertisement can associate a product with positive emotions, aspirational lifestyles, or societal ideals. Over time, consistent and effective marketing can embed these associations in consumers' minds, leading them to develop a preference for the advertised product. Moreover, endorsements from celebrities or influencers can further boost a product's appeal, especially among their followers. Thus, while consumers might believe their preferences are innate, many of them are, in fact, moulded by targeted marketing efforts.

Practice Questions

Explain how an increase in consumers' income might affect the demand for both normal and inferior goods.

An increase in consumers' income typically leads to a rise in the demand for normal goods, as these are products that consumers buy more of when their income rises. For instance, with more disposable income, consumers might opt for luxury items, branded products, or high-end services that they perceive as superior or desirable. On the contrary, the demand for inferior goods tends to decrease with a rise in income. Inferior goods are those that consumers turn to when they are budget-constrained. As their income increases, they often shift their consumption towards higher-quality alternatives, reducing their reliance on inferior goods.

How might the price increase of a substitute good influence the demand for a product? Provide an example.

When the price of a substitute good increases, the demand for the product it substitutes typically rises. This is because consumers will often switch to the cheaper alternative if the two goods can satisfy the same need or desire. For example, if the price of tea were to rise significantly, some consumers might switch to drinking coffee as an alternative source of caffeine. Thus, an increase in the price of tea could lead to an increase in the demand for coffee, as consumers look for a more cost-effective substitute.

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Written by: Dave
Cambridge University - BA Hons Economics

Dave is a Cambridge Economics graduate with over 8 years of tutoring expertise in Economics & Business Studies. He crafts resources for A-Level, IB, & GCSE and excels at enhancing students' understanding & confidence in these subjects.

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