Described herein are systems and methods for generating health or risk parameter reference intervals for use in healthcare or any other application of risk/attribute measurement. The reference intervals generated by the systems and methods described herein are based on direct analysis and evidence-based models of human and/or other living organism data from a population of individuals including shared feature(s) and outcome data such as vital status. The direct analysis and evidence-based models of human and/or other living organisms data utilize shared common risk parameter feature(s) and outcome data and identify relationships of two or more health or risk parameters relative to one another. These methods also apply to the measurement of risk and/or other attributes of any living organism or nonliving objects.