In the words of Taylor, 'scientific management means knowing exactly what you want men to do and seeing that they do it in the best and the cheapest way'.
It emphasises replacement of 'rule of thumb'  i.e. personal judgement, by scientific selected methods and tools.
Three principles of scientific management are:
(i) Science, not rule of thumb.
(ii) Harmony, not discord.
(iii) Cooperation, not individualism.

Meeting changing evvironment requirements 
Modern business environment is complex and everchanging, In order to survive sucessfully, organisations have to adapt to these changes.
Principles of management are dynamic in nature. They are flexible and frequently adapt to changes, which are favourable and profitable for the business.

Equity
This principle emphasises kindliness and justice in the behaviour of managers towards workers. It will bring loyalty and devotion in the behaviour of employees and they will put their best to achieve the targets.
For example, individuals performing similar jobs in kapura Ltd are paid at the same wage rate.
Order
As per this principle, there should be an orderly arrangement of men and material which implies that there is a fixed place for everything and everyone in the organisation.
A place for everything, called material order, and a place for everyone, called social order, ensures that there is no hindrance in the activity going on in the organisation.
For example, for the Head of Sales Department a cabin is alloted, for typist a single table and for a foreman a proper area should be alloted to supervise workers.
These individuals should remain in their allotted places during the working hours, so that they may be easily approached whenever necessary. Violation of this principle would cause and leads to inefficiency.

(i) Time Study
It determines the standard time taken to perform a well-defined job. Time measuring devices were used to conduct this study. This type of study is helpful in deciding the time required to perform a job. It also helps in determining incentive schemes and labour costs.
(ii) Motion Study
Motion Study refers to an in-depth study of movements of a worker while doing a task. Taylor recognised three types of movements:
(a) Productive   (b) UnProductive   (c) Incidental
The objective of motion study is to eliminate unproductive movements in doing a task to achieve efficiency and reduce the time required to do the task. for this, Taylor used stopwatches and various colours and symbols to idntify productive and unproductive movements of the employees.
(iii) Fatigue Study
Fatigue study seeks to find out the amount and frequency of rest intervals to be given to workers in completing task. This would help the worker to regain his stamina and work with the same efficiency again. It also aims to reduce various causes of fatigue such as long working hours, doing unsuitable work, bad working conditions, etc. The objective of this study is to find out how long a person can perform the standard task without any adverse effects on his health and productivity.
(iv) Method Study
This technique of scientific management is conducted to find out the 'one best method or way' of performing a particular task. The objective of this study is to minimise the cost of production and maximise the quality and satisfaction of the customer.
For this, techniques such as process charts and operations research are used.
(v) Simplification and Standardisation of work
Standardisation is the process of setting standards for every business activity, process, raw materials, time, machinery and methods, to achieve efficiency.
Standardisation of product implies that the size, design, quality, shape, etc of the product should meet the requirements and tastes of consumers.
The objective of standardisation are:
(i) To maintain quality standards.
(ii) To set up performance standards of men and machines.
(iii) To provide interchangeability of manufactured parts and products.
(iv) To achieve target production in pre-determined time. simplification means eliminating superfluous sizes, varieties and dimensions. Its aim is to:
(a) Eliminate unnecessary diversity of products and thereby reduce costs.
(b) Help in achieving economy in the use of required machines and tools.