Efficiency and Effectiveness
- Efficiency is often confused with effectiveness.
- Efficiency is quantitatively determined by the ratio of useful output to total useful input.
- Effectiveness is the ability to achieve a desired result.
- Efficiency can be expressed as a percentage of the ideal result.
- Efficiency can be indirectly quantified with a non-percentage value.

Inefficiency
- Inefficiency is the absence of efficiency.
- Allocative inefficiency refers to a mismatch between resource distribution and consumer preferences.
- Distributive inefficiency refers to the inefficient distribution of income and wealth.
- Economic inefficiency means a better job could be done at a lower cost.
- Keynesian inefficiency is caused by inadequate aggregate demand.

Types of Inefficiency
- Pareto inefficiency occurs when improving one person's situation worsens someone else's.
- Productive inefficiency means the given output could be produced at a lower cost.
- Resource-market inefficiency refers to barriers preventing full adjustment of resource markets.
- X-inefficiency relates to inefficiency in organizing people or production processes.
- Inefficiencies can be analyzed using data envelopment analysis.

Mathematical Expression
- Efficiency is often measured as the ratio of useful output to total input.
- It can be expressed as a mathematical formula.
- Efficiency is limited by the conservation of energy.
- Business efficiency is measured by comparing revenues to expenses.
- The Efficiency Movement advocated for efficiency in various aspects of society.

Efficiency in Other Sciences
- Algorithmic efficiency optimizes the speed and memory requirements of computer programs.
- Efficiency is a non-functional requirement in systems design and architecture.
- Efficiency factor is relevant in data communications.
- Storage efficiency measures the effectiveness of compute.
- Efficiency is a concept applicable in various scientific disciplines.