“By looking deeply at TPA models and their components, we were able to identify ‘enablers’ and ‘levers’ [essential components and variable components, respectively]. Through this framework, TPA models can be classified along a spectrum from ‘fully integrated’ to ‘partially integrated’ models with hybrid models along this spectrum existing in practice.” He found the use of a reference portfolio varies significantly from fund to fund and even when it’s used, what’s contained in it is different for investment organizations. In the CFA Institute’s report, Hayman spoke with a variety of institutional investors on a spectrum of TPA integration and found there’s multiple ways TPA can be adopted. When it comes to reviewing the performance of a TPA model, Trollor said proving the benefits or outcomes of a TPA approach with a single number is challenging.