Overall strength of evidence by outcome
| Outcome | Relevant studies | Evidence statement | Strength of evidence | Comments |
| Safety |
=Kellermann et al
12
=Little et al 13 =Middleton et al 17 =Poote et al 18 =Price et al 22 Madan26 | No evidence of a difference in risk between health professionals and symptom checkers | Weaker | Rating changed from stronger based on study numbers and design to weaker because of low numbers of adverse events reported |
| Clinical effectiveness |
−Little et al
13
?Madan26 | Insufficient evidence to draw any firm conclusions | Very limited | |
| Costs/cost effectiveness | +Babylon Health23
±Cowie et al 25 +Madan26 | Insufficient evidence to draw any firm conclusions | Inconsistent | |
| Diagnostic accuracy | ?Berry et al
15
−Berry et al 38 − Berry et al 16 − Price et al 22 ?Semigran et al 6 −Semigran et al 21 =Sole et al 19 | Symptom checkers appear inferior to health professionals in terms of diagnostic accuracy | Stronger | Mainly for specific conditions or preprepared vignettes |
| Disposition accuracy | =Babylon Health23
−Berry et al 16 =Middleton et al 17 ?Nijland et al 20 − Poote et al 18 ±Semigran et al 6 ±NHS England 7 | Inconsistent findings on accuracy of disposition | Inconsistent | Performance variable between different systems |
| Service use/diversion |
?Kellermann et al
12
±Little et al 13 ±Poote et al 18 ?Carter et al 24 ?Cowie et al 25 +Madan26 ±NHS England 7 +Babylon Health23 −Luger et al 33 | Inconsistent findings on effects on service use | Inconsistent | |
| Compliance | ?Nijland et al
20
?NHS England7 | No comparative data on compliance | Very limited | |
| Patient/carer satisfaction | ?Nagykaldi et al
35
?Nijland et al 20 ?Price et al 22 +Yardley et al 14 ?Carter et al 24 ?Cowie et al 25 ?Madan26 ?NHS England7 ?Lanseng and Andreassen30 | Most studies report high rates of patient satisfaction with symptom checkers and e-consultation systems generally | Weaker | Few studies with comparator data |
Controlled studies in bold; =means no significant difference in outcomes; +means better outcome with symptom checker; ±varying results within study; ? results difficult to interpret in comparative terms.