Psychologists employ empirical methods to infer causal and correlational relationships between psychosocial variables. Examples of research approaches include experiments, surveys, correlational studies, ethnographic research, and phenomenological inquiry. Such policy decisions can be grounded in, respectively, mechanistic evidence and correlational (econometric) studies. Correlational methods examine the statistical association between two naturally occurring variables. Is there a correlational, causal, or reciprocal relationship between knowledge and experience? Such correlational studies led to hypotheses about the causes of these crimes. However, further advancements showed that it is a correlational, not causal, relationship. Path analysis is a statistical technique that can be used with correlational data. Correlational and mechanistic models can be used in combination to gain additional insights. Most studies of minority stress are correlational. The main issue with forward inference is that it is a correlational method. Phenotypic integration may be the adaptive product of correlational selection. LeVay notes that these findings are correlational. Most epigenetic research is correlational; it merely establishes associations. Dennis Howitt (1995) disagrees with such research, arguing the weakness of correlational studies.