Constraints are things that prevent you from expanding your levels of activities. Constraints are usually seen as a bad thing not a good thing. However, they play an important role that not many people have recognised.
In consulting this may be the number of consultants you employ, the number of projects you are willing to undertake, or the number of priorities per week. Constraints represent positive bottlenecks and the aim is to maximise your utilisation and efficiency of your bottlenecks in your firm. They can be people resources (not just number of people, but the right mix of people), plant and equipment, production capacity, administration capacity, management capacity and so forth.
Generally the next constraint appears as soon as you debottleneck. Previously the bottleneck may have been your accounts payable department so you employed more people, and now your bottleneck may become your purchasing department.
For example, one of the things the Japanese manufacturing approach was very good at was leaving constraints in place and using them to drive innovation. The cost of the land was so high that they would not expand their warehouse but get their people to become more innovative through just in time inventory.
Constraints can be imposed on your firm to keep it lean and efficient. One way to make people more efficient and focus on value would be to impose a constraint on work hours. Make a rule that the office closes at 5.30pm and demand that people look to prioritise, focus and become more efficient. The newfound innovative mind-set will generate innovations well beyond what you expect and make it a better and sustainable business. In terms of breaking down a business plan, 90 days would be a very effective constraint that allows your team to focus on the immediate action plans and help clarifying what your people are doing.
Constraints enable you to think smarter and be more innovative, setting your firm up for success. They also challenge you to do more with less by working smarter, not working harder.