It is essential that any tool which is measuring outcome following head injury is sensitive to change over time. The Newcastle Independence Assessment Form-Research (NIAF-R) has been developed to be appropriate and applicable both in the acute situation and in the long-term. This paper illustrates the NIAF-R's level of sensitivity to change over time from eight weeks through to one year post-injury. There were no ceiling effects demonstrated at follow-up. Such effects can be a problem with other comparable measures. In addition, the results of further concurrent validation with the Barthel index, are reported. The NIAF-R scoring is refined through the development of an Adjusted Severity Indicator for more stringent analysis of level of independence. Scoring can now provide data in 55 individual areas of function for each subject or alternatively give an overall measure of severity of functional independence. Finally, this paper demonstrates the ability of the NIAF-R to predict outcome at follow-up.