A deadline can make a promise easier to judge. It can also give the impression of a plan before anyone has explained how the work will be done.
That is why I become sceptical when a government announces that a difficult social problem will be solved "by Christmas". The date sounds decisive. The useful questions concern the people, money and practical steps between the announcement and the result.
Who controls delivery?
A minister may depend on councils, contractors, services and people outside their direct control. Setting a deadline doesn't establish that those organisations have what they need or that their responsibilities fit together.
There is a good case for targets. Without a date, an institution can postpone work indefinitely. A clear objective can focus effort and expose delay. The difference is whether the target is connected to a credible account of delivery.
Who owns each part? What has to happen first? What would show that the plan is falling behind? What will change if it is?
Measure the problem rather than the appearance
A deadline can also encourage work that improves the reported figure without resolving the underlying need. With rough sleeping, for example, getting someone indoors for a night and helping them into stable accommodation are different achievements. Both may be useful, but one shouldn't be presented as the other.
That isn't proof that a particular minister intends to manipulate the count. It is a reason to define success carefully and check what the number means.
I would like a deadline to begin a more demanding conversation. A date should come with a method, resources and responsibility, followed by an honest account of the outcome. Otherwise the public receives the confidence of an announcement while the people the promise concerns are still waiting for a workable plan.