People get contacted depending on the type of the nature of the job, the amount of people required, the urgency of the project or certain procedural requirements. In other words, it depends on the discretion of the management and the HR department (Human Resources department) to contact the interviewees. Individual who have given the oral interview are either contacted by the HR team for another round of interview (an HR interview, process related interview or another round of written test) or for the offer letter.
As mentioned in the above paragraph, the time in which an individual is contacted depends upon the job requirement or the nature of the job. For instance, in sectors like BPOs (Business Processing Outsourcing), there is a high attrition rate and people are hired in an increased number. So chances are that you can be asked to wait and take the offer letter/appointment letter that particular day itself! In certain fields like civil services, there is a certain amount of time like 2 months or so which can pass after an oral interview before the interviewee is contacted. At times people are screened for background checks, before being contacted again to be hired.
As mentioned in the above paragraph, the time in which an individual is contacted depends upon the job requirement or the nature of the job. For instance, in sectors like BPOs (Business Processing Outsourcing), there is a high attrition rate and people are hired in an increased number. So chances are that you can be asked to wait and take the offer letter/appointment letter that particular day itself! In certain fields like civil services, there is a certain amount of time like 2 months or so which can pass after an oral interview before the interviewee is contacted. At times people are screened for background checks, before being contacted again to be hired.