The authors are engaged in on-going research on the functionality of Electronic Health Records (EHR) software, and challenges doctors face as they migrate from paper to electronic-based record keeping. Our goal is to assist healthcare providers in the adoption of EHR software and in the optimization of their clinical and practice management functions. Healthcare providers face increasing pressure to adopt an EHR, if they haven't already done so. Providers should temper their response to this pressure and avoid blind faith selection. In this paper, we review the meaning of trust, and introduce a measure of trustworthiness. This measure is used to rank cloud-based EHR solutions. The trustworthiness measure quantifies how well an EHR satisfies the provider needs and critical operational requirements. The trustworthiness measure uses a certainty factor to weigh the quality of evidence used to evaluate the EHR. The trustworthiness model provides a framework for contextualizing and prioritizing important selection considerations, and can be used with risk mitigation strategies to improve decision making when selecting an EHR.