Managing strategy very often involves change-this will include the need to understand how the context of an organisation should influence the approach to change; the different types of roles for people in managing change. It also looks at the styles that can be adopted for managing change and the levers by which change can be effected. 102. Structural types(397) define the 'levels' and roles in an organisation. They are important to managers not just because they describe who is responsible for what. Formal structures matter in at least two more ways. First, structural reporting lines shape patterns of communication and knowledge exchange: people tend not to talk much to people much higher or lower in the heirarchy, or in different parts of the organisation. Second, the kinds of structural positions at the top suggest the kinds of skills required to move up the organisation: a structure with functional specialists such as marketing or production at the top indicates the importance to success of specialised functional disciplines rather than general business experience. In short, formal structures can reveal a great deal about the role of knowledge and skills in an organisation. There are seven basic structural types: functional, multidivisional, holding, matrix, transnational, team and project. Broadly, the first three of these tend to emphasise one structural dimension over another, for instance functional specialisms or business units. The four that follow tend to mix structural dimensions more evenly, for instance trying to give product and geographical units equal weight. However, none of these structures is a universal solution to the challenges of organising. Rather, the right structure depends on the particular kinds of challenges each organisation faces. 103. Substitution(78,82,132,262,465,479) reduces demand for a particular 'class' of products as customers switch to the alternatives –even to the extent that this class of products or services becomes obsolete. This depends on whether a substitute provides a higher perceived benefit or
value. Substitution may take different forms: There could be product-for-product substitution. There may be substitution of need by a new product or service, rendering an existing product or service redundant. Generic substitution occurs where products or services compete for disposable income. So some industries suffer because consumers decide to 'do without' and spend their money elsewhere. In the public sector different services (education, health, defence etc.) compete for a share of public spending. 104. Success criteria(357)are used to judge the likely success or failure of a strategic option. There are three main successcriteria: Suitability is concerned with whether a strategy addresses the circumstances in which an organisation is operating –the strategic position.