But crowdsourcing works better for some kinds of problems than for others. For instance, it requires fast and efficient ways to test a large number of potential solutions. If testing is very time-consuming and costly, you need some other approach, such as soliciting a handful of solutions from just a few experts or organizations. Similarly, crowdsourcing tends to work best for highly modular systems, in which different problem solvers can focus on specific components without worrying about others.