Spontaneous intracerebral hemorrhage, the non-traumatic rupture of cerebral blood vessels, is the most devastating form of stroke. The disease is dynamic, unpredictable, and patients can worsen acutely within the first 24 hours secondary to hematoma expansion: re-bleeding of a baseline hemorrhage. Hematoma expansion is a major predictor of mortality and poor long-term outcome. This secondary analysis thesis proposes to advance the current understanding of this phenomenon through three separate research endeavors: 1) a scoping review of hematoma expansion prediction scores, 2) an independent validation of a non-contrast prediction score, and 3) an assessment and revision of the dichotomous definition of hematoma expansion used in clinical trials. These three projects will offer different contributions that will advance the science of intracerebral hemorrhage, a field where treatment options, outcome measures, and basic definitions, are all under active debate.