HRP is influenced by several factors. The most important of the factors that affect HRP are (1) type and strategy of organization (2) organizational growth cycles and planning (3) environmental uncertainties (4) time horizons (5) type and quality of forecasting information (4) nature of jobs being filled and (5) off loading the work.

1. Type and Strategy of the Organization: Type of the organization determines the production processes involve, number and type of staff needed and the supervisory and managerial personnel HR need is also defined by the strategic plan of organization. If the organization has a plan for organic growth then organization need to hire additional employees. On the other hand If the organization is going for mergers and acquisition, then organization need to plan for layoffs, as mergers can create, duplicate or overlap positions that can be handled more efficiently with fewer employees.

Organization first decides whether to be reactive or proactive in HRP. Organizations either carefully anticipate the needs and systematically plan to fill the need in advance (proactive) or can simply react to the needs as they arise (reactive). Likewise, the organization must determine the width of the HR plan. Organization can choose a narrow focus by planning in only one or two HR areas like recruitment and selection or can have a broad perspective by planning in all areas including training and remuneration.

The nature of HR plan is also decides upon the formality of the plan. It can decides to have an informal plan that lies mostly in the minds of the managers and personnel staff or can have a formal plan which is properly documented in writing

The nature of HR plan is also depended upon the flexibility that is practiced in the organization. HR plan should have the ability to anticipate and deal with contingencies. Organizations frame HRP in such a way that it can contain many contingencies, which reflect different scenarios thereby assuring that the plan is flexible and adaptable.

1. Organizational Growth Cycles and Planning: All organizations pass through different stages of growth from the day of its The stage of growth in which an organization is determines the nature and extends of HRP. Small organizations in the earlier stages of growth may not have well defined personnel planning. But as the organization enters the growth stage they feel the need to plan its human resource. At this stage organization gives emphasis upon employee development. But as the organization reaches the mature stage it experience less flexibility and variability resulting in low growth rate. HR planning becomes more formalized and less flexible and less innovative and problem like retirement and possible retrenchment dominate planning.

During the declining stage of the organization HRP takes a different focus like planning to do the layoff, retrenchment and retirement. In declining situation planning always becomes reactive in nature towards the financial and sales distress faced by the company.

3. Environmental Uncertainties: Political, social and economic changes affect all organizations and the fluctuations that are happening in these environments affect organizations Personnel planners deal with such environmental uncertainties by carefully formulating recruitment, selection, training and development policies and programmes. The balance in the organization is achieved through careful succession planning, promotion channels, layoffs, flexi time, job sharing, retirement, VRS and other personnel related arrangements.
4. Time Horizons: HR plans can be short term or long Short term plans spans from six months to one year, while long term plans spread over three to twenty years. The extent of time period depends upon the degree of uncertainty that is prevailing in an organizations environment. Greater the uncertainty, shorter the plan time horizon and vice versa.

Table 2.1 : Degree of Uncertainty and Length of Planning Period

Source: Elmer H. Burack and Nicholas J. Mathis, Human Resource Planning- A Pragmatic approach to manpower Staffing and development, Illinosis, Brace- Park Press, 1987, p. 129.

5.Type and Quality of information: The information used to forecast personnel needs originates from a multitude of The forecast depends to a large extent upon the type of information and the quality of data that is available to personnel planners. The quality and accuracy of information depend upon the clarity with which the organizational decision makers have defined their strategy, structure, budgets, production schedule and so on.

6.Nature of Jobs Being Filled: Personnel planners need to be really careful with respect to the nature of the jobs being filled in the Employees belonging to lower level who need very limited skills can be recruited hastily but, while hiring employees for higher posts, selection and recruitment need to be carried out with high discretion. Organization need to anticipate vacancies far in advance as possible, to provide sufficient time to recruit suitable candidate.

7. Outsourcing: Several organizations outsource part of their work to outside parties in the form of Outsourcing is a regular feature both in the public sector as well as in the private sector companies. Many of the organizations have surplus labour and hence instead of hiring more people they go for outsourcing. Outsourcing is usually done for non critical activities. Outsourcing of non- critical activities through subcontracting determines HRP.