Whenever you have more than 3 stairs either outside or inside, it’s always recommended that there be adequate hand rails / railings that you can grab on to both for support and in the event that you or someone trips and starts tumbling / falling down. The important thing with railings is to have handrails / railings that you or a child can grab onto by wrapping your hands easily around the railing(s). 2x4 wood studs do not qualify as adequate railings because you can’t grab on to them.
Additionally, for child safety reasons, no vertical or horizontal railings should have more than 4 inch spacings between them at any area if the stairs are above 30 inches in height ( these height levels vary from community to community…so please consult your local building and safety department for height requirements ).
So, always be sure to have approved wood or metal railings installed at the appropriate heights so that they can be easily grabbed on to in the event of a fall or just for support while going up or down stairs.