Sample Questions Intervention Question In Mexican-Americans male adults with lupus (P), how does Cortisol-corticosteroid (I) compared to azathioprine-Immunosuppressive (C) affect kidney function (O)? Etiology Question Are women between 18 and 35 years (P) who have given birth (I) compared to those who have not given birth (C) at higher risk for developing cervical cancer (O) within the first 5 years of oral contraception use (T)? Therapy Question In adolescents with Attention Deficit and Hyperactivity Disorder (ADHD) (P), what is the effect of Parent-Child Interaction Therapy (I) compared to Parent Management Training (C) on development of the adolescent’s relationships? In EBP, you should aim to use systematic reviews as first choice source of information. This is because they are usually considered “Level I Evidence”. Systematic reviews are usually determined by; 1. their address of focused and clearly designed question, and 2. their use of systematic and explicit methods in identifying, selecting, and examining relevant research as well as collecting and analyzing data in the studies encompassed in the review. However, it is clear that there lacks systematic reviews for every nursing clinical question. The nurse is therefore obligated to look for other types of studies. Notably, the level of evidence for different category of questions vary from one study to another. This is as illustrate below.
| Type of Question | Type of Study with Highest Evidence Level |
| Diagnosis | Cohort study with all subjects receiving both the study test as well as the gold standard reference test. |
| Intervention/ Therapy | Randomized controlled trial |
| Prognosis | Longitudinal cohort |
| Etiology/Risk factors | Cohort for rare/uncommon exposure with similar outcome Randomized controlled trial |