Final answer:
In assessing internal validity, we determine if changes cause outcomes through controlled experiments where random assignment helps eliminate lurking variables, thereby testing hypotheses about causal relationships.
Step-by-step explanation:
In assessing the internal validity of an intervention, we aim to determine if certain changes cause certain outcomes. This process is often carried out through a controlled experiment where researchers manipulate one or more independent variables to observe the effect on a dependent variable, while controlling for extraneous factors. Random assignment of subjects to different treatment groups is a critical feature of this approach, helping to eliminate the influence of lurking variables. Well-designed experiments allow for testing hypotheses with if-then statements, providing clear evidence to support or refute a causal relationship between variables.
For instance, a researcher might hypothesize that introducing a specific educational technology improves student learning outcomes. They would then design an experiment where one group of students uses the technology while another group does not. If the study is properly controlled and results show a significant difference in learning outcomes, the researcher may conclude that the technology has a causal effect on learning.