Marginal productivity refers to the additional output that is produced when one extra unit of a factor of production is added while keeping all other factors of production constant. It is an important concept in economics as it helps in determining the productivity of an individual worker or a factor of production.

Factors affecting marginal productivity
There are several factors that affect marginal productivity such as:

- Technology
- Education and training of workers
- Availability of factors of production
- Quality of factors of production
- Nature of the production process
- Efficiency of the production process

Importance of marginal productivity
Marginal productivity is important for businesses and the overall economy as it helps in determining the optimal amount of resources to be used in production. Businesses can use this concept to determine the number of workers they need to hire to produce a certain amount of output. They can also use it to determine the optimal amount of capital to be used in production.

Calculating marginal productivity
Marginal productivity can be calculated using the following formula:

Marginal Productivity = Change in Output / Change in Input

For example, if a factory produces 100 units of output with 5 workers and 110 units of output with 6 workers, then the marginal productivity of the 6th worker would be calculated as:

Marginal Productivity = (110 - 100) / (6 - 5) = 10

In this case, the marginal productivity of the 6th worker is 10 units of output.

Conclusion
Marginal productivity is an important concept in economics that helps in determining the productivity of an individual worker or a factor of production. It is important for businesses and the overall economy as it helps in determining the optimal amount of resources to be used in production.

The amount of contribution made by last unit of labour. if it is measured physiclally it is called marginal physical product & if it is measured in value it is called marginal revenue product or value of marginal product.