Goldsmith uses the three uniities She Stoops to Conquer:
The Unity of Action - This is the one Unity that Goldsmith does not rigorously follow; there is the inclusion of the Constance-Hastings eloping sub-plot that distracts from the main narrative of the play. However, it shares similar themes of relationships and what makes the best ones (mutual attraction or the arrangement of a parent or guardian). Furthermore, the sub-plot is inter-weaving with the main plot, for example, when Hastings and Marlow confront Tony regarding his mischief making.
The Unity of Time - The alternative title of Mistakes of the Night illustrates that the Unity of Time is carefully observed. With all of the events occurring in a single night, the plot becomes more stimulating as well as lending more plausibility to the series of unlucky coincidences that conspire against the visitors.
The Unity of Place - Whilst some may question whether She Stoops to Conquer contains the Unity of Place — after all, the scene at the "The Three Pigeons" is set apart from the house — but the similarity between the alehouse and the "old rumbling mansion, that looks all the world like an inn" is one of close resemblance; enough that in past performances, the scenes have often doubled up the use of the same set backdrop. Also, there is some debate as to whether the excursion to "Crackskull common" counts as a separate setting, but since the truth is that the travellers do not leave the mansion gardens, the Unity of Place is not violated.