The burn multiple, popularized by David Sacks, measures capital efficiency of growth: net burn over a period divided by net new ARR added in that period. A multiple of 1 means the company burned a dollar to add a dollar of recurring revenue; on Sacks’s scale under 1x is amazing, 1 to 1.5x great, 1.5 to 2x good, 2 to 3x suspect, above 3x bad, and the ratio rises sharply as a company stalls. Its appeal is that it captures in one number whether growth is being bought cheaply or expensively.
The structural caveat for deep tech is that the metric is defined only when there is recurring revenue to put in the denominator. A pre-revenue robotics company has net new ARR of zero, so the burn multiple is either infinite or undefined; computing it is meaningless, and dressing burn up as a multiple against a sliver of NRE or pilot revenue is worse than not reporting it. The metric belongs to the post-traction phase, after a repeatable revenue line exists.
The honest pre-revenue substitute is to express efficiency against milestones rather than revenue: how much capital is consumed to reach the next proof that re-rates the company (a demonstrator, a regulatory clearance, a qualified system). That figure is the deep tech cousin of capital efficiency, it lets a board compare planned against actual spend per unit of de-risking, and it sets up the burn multiple to be used properly once recurring revenue finally arrives. Reporting milestone cost pre-revenue and the burn multiple post-revenue is the credible sequence; forcing the multiple early is a tell that the metrics were chosen to flatter rather than to inform.