It is important for big things to start small and many attempts to replicate DARPA’s results start too big. Most DARPA clones start too big or with heavy process. So it makes sense to ask: can you start with a tenth of DARPA’s budget? A hundredth? A thousandth?
There are two lower budget bounds that you’ll run into: the number of parallel high-risk programs you need to run to get a success and the budget per program to have a viable shot at that success.
A back of the envelope calculation suggests that if each program generously has a 10% chance of success DARPA has a 5-10 percent program success rate then you need to run at least seven programs to give yourself a 50% chance of at least one program being successful.
The question of minimum program budget is trickier. Let’s look at some comparison numbers. In the years 2018-2020 among DARPA programs not focused on assembly and production, the minimum budget was $2m, the maximum budget was $31.4m and the average budget was $12m. The ARPA IPTO directorate that midwifed the personal computer started with a budget of $47M in today’s dollars. ARPA-E vacillates between ~$200-$300M/year, has about 50 programs running at any time, which comes out to roughly $4m to $6m per program. IARPA’s budget is classified. Could a program go below a couple million dollars a year and still be effective? There are arguments both ways. On the one hand you could argue that surely bureaucratic inefficiency is pushing those budgets higher than they need to be. On the other hand, it might be that the sort of work that it’s most valuable for an organization riffing on the ARPA Model to do needs a relatively large budget, otherwise it would be picked up by other funding mechanisms.
According to ARPA Does Windows - The Defense Underpinning of the PC Revolution, the ARPA IPTO directorate started with a budget of $7M ($47M today.)
In the years 2018-2020 among DARPA programs not focused on assembly and production, the minimum budget was $2m, the maximum budget was $31.4m and the average budget was $12m.