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tokens: 1.6%, subdominant in regard to time-delay measurements, the angular lens model component, and the line-of-sight convergence of the TDCOSMO sample of seven lenses. Similar considerations apply to the future scenarios illustrated in Figs. 3 and 4 , except for the precision that reaches 1.2–1.5% by virtue of the larger samples. A significant component of the error budget at the 1% level arises from the uncertainty in the relative expansion history of the Universe (in our case the prior on Ω m ). It is encouraging that, thanks to the external datasets, we can reach a similar precision to that forecasted by Shajib et al. (2018) . These latter authors broke the MST by assuming the mass profile is a power law. We break it with spatially resolved kinematics and external datasets. Fig. 3. Forecast precision on H 0 , the MST parameter λ , and the anisotropy parameter a ani for different spectroscopic scenarios of a future sample of 40 TDCOSMO lenses (future scenario) as specified in Table 1 in the row of TDCOSMO-5% ( https://github.com/sibirrer/TDCOSMO_forecast/blob/master/forecast.ipynb ). Fig. 4. Forecast precision on H 0 , the MST parameter λ , and the anisotropy parameter a ani for different spectroscopic scenarios of a future sample of 40 TDCOSMO lenses (future scenario) observed with aperture spectroscopy of 5% precision and additional external data sets specified in Table 1 in the row of TDCOSMO-5% ( https://github.com/sibirrer/TDCOSMO_forecast/blob/master/forecast.ipynb ). 5. Conclusions We describe two strategies to measure H 0 with 2.5–3.5% precision with gravitational time delays while accounting for the uncertainty introduced by the mass-sheet transformation. The first is based on current samples of 7 time-delay lenses and existing technology and the second is based on adding 50 nontime-delay lenses. The same strategies, applied to a future sample of 40 time-delay and 200 nontime-delay lenses can achieve 1.2–1.5% precision. The keys to achieving this precision are spatially resolved kinematics and the inclusion of datasets of nontime-delay lenses in a hierarchical framework. These two strategies are not mutually exclusive and both should be pursued. The TDCOSMO-only approach has the advantage of not relying on the assumption that the time-delay and nontime-delay galaxies are drawn from the same parent population. With this additional assumption, the TDCOSMO+external approach allows for further improvement in precision. The precision of each approach is sufficient to test the mutual consistency among different samples while simultaneously fitting for H 0 . If verified, potentially with the extension of the hierarchical framework, the consistency will enable the cosmological exploitation of larger samples of nontime-delay lenses that are expected to be discovered by future surveys ( Oguri Marshall 2010 ). Following our proposed strategies, time-delay cosmography will, in the near future, have sufficient precision to distinguish the current