Problem: A team of researchers is examining the efficacy of cognitive-behavioral interventions for smoking cessation for adults 65 years and older. Dr. Frommer begins a literature search at three major library databases using keyword search terms. A total of 150 articles were found and 26 articles met the study's inclusion criteria. The team found moderate effect sizes and significant findings for the efficacy of cognitive-behavioral interventions targeted for adults 65 years and over. What type of study is being described?