Performance-based research funding systems have been extensively used around the globe to allocate funds across higher education institutes (HEIs), which led to an increased amount of literature examining their use. The UK's Research Excellence Framework (REF) uses a peer-review process to evaluate the research environment, research outputs and non-academic impact of research produced by HEIs to produce a more accountable distribution of public funds. However, carrying out such a research evaluation is costly. Given the cost and that it is suggested that the evaluation of each component is subject to bias and has received other criticisms, this article uses correlation and principal component analysis to evaluate REF's usefulness as a composite evaluation index. As the three elements of the evaluation--environment, impact and output--are highly and positively correlated, the effect of the removal of an element from the evaluation leads to relatively small shifts in the allocation of funds and in the rankings of HEIs. As a result, future evaluations may consider the removal of some elements of the REF or reconsider a new way of evaluating different elements to capture organizational achievement rather than individual achievements.