AP Syllabus focus: ‘Productivity depends on technology and the amount of physical and human capital available per worker.’
Productivity explains why some economies produce more output with the same labour input. In AP Macroeconomics, the key determinants are technology, human capital, and physical capital per worker.
Productivity and output per worker
Productivity is commonly discussed as output per worker (average labour productivity).
U.S. labor productivity over time, plotted as an index of output per hour worked (1947–2020). The upward trend illustrates how sustained increases in output per hour—i.e., labor productivity—accumulate into much higher long-run production capacity. Source
When productivity rises, firms can produce more real output with the same number of workers, supporting higher sustainable living standards.
Labour productivity (output per worker): real output produced per employed worker over a given period.
A useful organising idea is that productivity improves when workers:
have better tools and machines (more/better capital),
have more skills and knowledge (human capital),
can use improved methods and innovations (technology).
The three determinants
Technology (A): ideas, methods, and efficiency
In macro, technology includes more than computers; it is the overall efficiency of production—new processes, better management, improved logistics, and scientific advances. Technology raises productivity by allowing:
the same inputs to generate more output (higher efficiency),
fewer inputs to generate the same output (cost-saving production),
new goods and higher-quality goods that expand what can be produced.
Technology often shows up as an increase in total factor productivity (TFP)—output rising faster than measured inputs.
Technology (TFP): improvements in how efficiently labour and capital are combined, including innovations, better processes, and organisational know-how.
Human capital: skills embodied in workers
Human capital is the productive value of workers’ education, training, health, and experience. It raises productivity because workers can:
operate complex machinery and software,
adapt to new technologies and tasks more quickly,
commit fewer errors and produce higher-quality output,
innovate and improve processes on the job.
Human capital: the knowledge, skills, training, and health that workers possess, which increase their ability to produce goods and services.
Human capital is especially important for sustaining productivity gains from technology: advanced tools require workers who can use and maintain them effectively.
Physical capital per worker: tools, machines, and structures
Physical capital includes equipment, factories, vehicles, computers, and infrastructure used in production. When capital per worker rises (often called capital deepening), each worker has more or better tools, which tends to increase output per worker. Key channels include:
higher speed and precision of production,
ability to produce goods that are impossible with hand labour alone,
reduced downtime and improved reliability.
Physical capital: man-made productive resources (machines, buildings, equipment, infrastructure) used to produce goods and services.
Even with more capital, productivity gains may slow due to diminishing marginal returns to additional capital when technology and skills are unchanged (each extra machine helps, but by less than the previous one).
Pulling it together: the production function perspective
Economists summarise these relationships with an aggregate production function that highlights technology and inputs per worker.
= real output (real GDP)
= technology / total factor productivity (index)
= physical capital stock (real units)
= human capital (skill/education/health-adjusted labour input)
= labour (number of workers or hours)
Interpreting the function:
higher A raises output from any given combination of inputs,
higher K and H (especially per worker) typically raise output per worker,
the biggest sustained productivity improvements usually involve complementary increases in A, human capital, and capital deepening.
FAQ
Often inferred as total factor productivity (TFP): the part of output growth not explained by measured growth in labour and capital. It is a residual, so it can reflect measurement error too.
Labour (L) counts workers or hours. Human capital adjusts labour for quality—skills, education, experience, and health—so two economies with the same L can have different H.
Because of diminishing marginal returns: with fixed technology and skills, each additional unit of capital has less extra output to work with (e.g., too many machines for the same workforce to use efficiently).
Yes. Productivity-relevant human capital can increase via:
better on-the-job training
improved health and nutrition
higher-quality education (not just quantity)
learning-by-doing and experience gains
Innovations can generate positive externalities (knowledge spillovers) when ideas spread across firms and industries, raising productivity beyond the innovating firm’s private gains.
Practice Questions
(2 marks) Define human capital and state one way it can increase labour productivity.
1 mark: Correct definition of human capital (skills/education/training/health embodied in workers).
1 mark: One valid channel (e.g., improves ability to use technology, reduces errors, increases output per hour).
(6 marks) Using the production function framework, explain how an increase in technology and an increase in physical capital per worker affect labour productivity.
1 mark: States a production function relationship (e.g., ) or clearly links output to A and K.
2 marks: Explains technology increase raises efficiency/TFP so more output from same inputs (higher output per worker).
2 marks: Explains higher physical capital per worker (capital deepening) gives workers more/better tools, raising output per worker.
1 mark: Notes interaction/complementarity or mentions diminishing marginal returns to capital if A and skills are unchanged.
