Hand timed performances are on the rankings as not all competitions can provide electronic timing. If we didn’t include the hand times the rankings list would not be representative, especially in the younger age groups where it would be more difficult to ensure all athletes can have electronically timed races.
We use a system that orders as 11.20, 11.2 and 11.21 in the rankings, so 11.2 hand timed is lower down than 11.20 electronic. In general, a hand timed 11.7 would mean that multiple timekeepers have timed as 11.61-11.70 so likely to be correct.
Hand times in the UK are considered more accurate than they perhaps would be elsewhere.
For senior and U20 sprint events (100/200/sprint hurdles) we have an electronic timed limit set. Athletes who have achieved times near the top of the rankings must have achieved them electronically. Hand times will then only appear after this.