Research is undertaken to answer questions through a systematic process. It aims to find solutions to problems, understand causes and effects, and assess outcomes. High quality research builds upon previous work, can be replicated, applies to other contexts, and generates logical, testable hypotheses. Research uses both theoretical frameworks and empirical observations to explore relationships between variables in a probabilistic and often causal manner. Studies can be descriptive, relational, or causal, and take a cross-sectional or longitudinal approach over time. Hypotheses make specific, testable predictions about expected relationships between independent and dependent variables. Research relies on quantitative and qualitative data from both primary and secondary sources.