Organization size certainnly has an impact on HR function, since HR plays various roles in an organization, starting with recruitment, selection training & development and managing employee performance. As a result, impacting HR strategy and function to carry out the necessary administrative support for managing the increase in the organizations workforce.
Another aspect of HR function that is affected by the size of an organization is departmentalization, which establishes how jobs are grouped together and provide the large workforce with clearly defined tasks in order to keep the organization running efficiently, as a result upgrading and modifying the organizational hierarchy, updating job descriptions, advancing HR processes and function to control the expansion.
An example from the growth of an organisation.
When the airline was established in the 1980s, operating only domestic flights, it had only 5 HR staff to manage the administrative work for the entire organization that had less than 150 staff.
Currently, in 2015, with a headquarter campus and over 9000 staff, HR is now a large department that constitutes of many sections such as:
Recruitment to attract new talent and accommodate the expansion of fleet and hire the operational and administrative staff needed to run the operations.
Payroll section has been established to run separately as a unit responsible of all benefits and remunerations of the workforce.
Performance and training section responsible over staff appraisal, career developments plans and provide the necessary training.
In addition to, Budget section, Policies and Procedures Section and Employees Welfare Section.
So Yes! Organization size does have an impact on HR function.