There are 169 targets which specify the 17 goals (each goal has typically 8-12 targets). They are shown in detail in the list of SDG targets and indicators. Each target has between 1 and 3 indicators used to measure progress toward reaching the targets.
The targets are distinguished into “outcome” (circumstances to be attained) and “means of implementation” targets. The latter targets were introduced late in the process of negotiation of the SDGs. They provided a way to accommodate some of the concerns of Member States regarding how the SDGs were to be achieved. The first 16 SDGs have mainly outcome targets (which use numbers, for example Target 6.1) but also some “means of implementation” targets (which use letters, for example Target 6.a). Goal 17 is wholly about how the SDGs will be achieved.[