'vertical fit'. This implies according to them informal, more flexible, styles of HRM among start-up
organizations and more formal, professionalized styles as organizations become more mature and increase the
number of their employees. They also argue for 'internal fit', for the need to ensure that individual HR policies
are designed to 'fit with and support each other'; something they call it 'horizontal fit' (Boxall and Purcell,
2000).