reformat in laymans terms in 3-5 senteces only; Internal validity ensures that changes in the dependent variable are genuinely caused by the independent variable, not by other factors. Factors affecting internal validity include outside events, natural changes, testing effects, measurement tools, statistical issues, participant selection biases, and morale. External validity, on the other hand, determines if findings can be applied to larger groups or different situations. Researchers can enhance external validity using designs like the Solomon four-group design. To address threats to both types of validity, strategies such as using control groups can help minimize the impact of outside events and maturation effects (Berga, 2023)