Previous studies have defined a new type of impairment in which an able-bodied user's behaviour is impaired by both the characteristics of a device and the environment in which it is used. This behavioural change is defined as a situationally-induced impairment and is often associated with small devices used in a mobile setting or constrained environment. Relatively little is known of its extent or the magnitude of the problems faced by the user. Here, we place the work that has been undertaken into a comparative framework of impairment in the context of data input. Our survey finds that 12 problems exist which define all impaired input and we look to understand the similarities and possible solutions in the new impairment group of small device users. For instance, from the literature, we find that users who are both situationally and motor impaired: press keys more than once, do not use enough force and so a key is not activated, and accidentally type keys in reverse order. A wealth of other errors exist in the motor impaired domain but work does not exist to support their existence in the situational domain. However, if commonalities exist for some - it seems work should be enacted to uncover the commonalities of all. Establishing these possible commonalities is important because solutions from one domain can be leveraged into another thereby saving the need to reinvent interventions which already exist elsewhere.