The sequence of development is the order in which certain milestones are reached or accomplished. Some orders of a child’s sequence of development are set, for example, a child will not be able to run before they can walk or sit upright unaided before they can hold their own head up. But some orders of sequence may vary from one child to another. For example, in the physical development of a baby, one child may pull themselves up to stand and cruise around with the aid of furniture before they attempt to crawl, whilst another may be crawling but not yet pulling themselves up to cruise. Both children will eventually be able to do both but the sequences in which they meet these accomplishments are different.
The rate of development is the speed or timing at which a child reaches milestones, and this will also vary from child to child. For example, in the physical development of a baby, one may begin to walk at 10 months while another may still just be crawling and not walk until 15 months. Another example, in the physical development of a teenager, is that one adolescent female may begin to develop breasts at the age of 10 whilst another’s development in that area may not be until later in their early teens. Again, both subjects within these examples will reach these milestones but they will do so at different times.
There must be a distinction between the rate and sequence of development as children will naturally progress at different speeds. Individuals may reach milestones in different aspects at different rates, with a child showing greater prowess in one area than another. For example, a child that is not walking before turning one year old may be more advanced with their speech than a child who is walking.
Therefore it is important to take into account the individual rates and sequences of all aspects of a child’s development when assessing them, to establish the areas in which each child may need to be supported or encouraged.