The career path of IAS officers is well defined. About 60 to 90 officers are inducted every year from about 300,000 applicants based on the results of a competitive civil service examination. Training for IAS officers is also noted for its rigor.
The precursor of the IAS was the Indian Civil Service (ICS) during the British Raj era. ICS officers (known as "Collectors"), were generally held in high regard as incorruptible and good administrators. There were critics, however; Jawaharlal Nehru recounted a popular saying that the ICS was "neither Indian, nor civil, nor a service" in his Discovery of India. British Prime Minister David Lloyd George referred to the colonial ICS as the "steel frame" of the British Raj for its role in influencing and implementing government policies and decisions.
Upon independence, the new Republic of India accepted the then serving Indian Civil Service officers who chose to stay on rather than leave for the UK, and renamed the service the Indian Administrative Service.
After being selected for the IAS, candidates are allocated to "cadres." There is one cadre in each Indian state, except for three joint cadres: Assam-Meghalaya, Manipur-Tripura, and Arunachal Pradesh-Goa-Mizoram-Union Territories (AGMUT).
The "insider-outsider ratio" (ratio of officers who are posted in their home states) is maintained as 1:2. as 'insiders'. The rest are posted as 'outsiders' according to the 'roster' in states other than their home states. Till 2008 there was no choice for any state cadre and the candidates , if not placed in the insider vacancy of their home states, were allotted to different states in alphabetic order of the roster, beginning with the letters A,H,M,T for that particular year. For example if in a particular year the roster begins from 'A', which means the first candidate in the roster will go to the Andhra Pradesh state cadre of IAS, the next one to Bihar, and subsequently to Chattisgarh, Gujarat and so on in alphabetical order. The next year the roster starts from 'H', for either Haryana or Himachal Pradesh.(if it has started from Haryana in the previous occasion when it all started from 'H', then this time it would start from Himachal Pradesh). This highly intricate system has on one hand ensured that officers from different states are placed all over India, it has also resulted in wide disparities in the kind of professional exposure for officers, when we compare officers in small and big & also developed and backward state, since the system ensures that the officers are permanently placed to one state cadre. The only way the allotted state cadre can be changed is by marriage to an officer of another state cadre of IAS/IPS/IFS. One can even go to his home state cadre on deputation for a limited period, after which one has to invariably return to the cadre allotted to him or her.
The centralizing effect of these measures was considered extremely important by the system's framers, but has received increasing criticism over the years. In his keynote address at the 50th anniversary of the Service in Mussoorie, Cabinet Secretary Nirmal Mukarji argued that separate central, state and local bureaucracies should eventually replace the IAS as an aid to efficiency. There are also concerns that without such reform, the IAS will be unable to "move from a command and control strategy to a more interactive, interdependent system".
IAS officers time scales:
The State Governments however have a kind of a leverage to post these officers. Normally when an IAS officer joins the State, he is placed as a Sub Divisional Magistrate (SDM). Ideally he is to be made in charge of a District after completing 9 years of service and entering the Junior Administrative Grade but in certain States, even younger IAS officers are made in charge of Districts (Known as District Magistrates (DM), Deputy Commissioners (DCs) or Collectors).