Developing a System

I am revisiting an interview I did with LTC Ken Long, a systems expert with the U.S. Army.  Here’s what Ken said about developing a system:

Define Who You  Are:  “Before you conduct any planning or system design, you must have a thorough understanding of who you are and what your objectives are.  Individual investors, private hedge fund managers, public mutual fund managers, and trust managers will have different dynamics, time frames, and risk profiles. This relates to system design in that the final product must fit the circumstances and dynamics of the group or individual.  If you jump into system design without considering these basics, you will sow the seeds of future problems.”

Objectives:  “In trading system design, the problem is to define what you want the system to accomplish.  With as many ideas, events, circumstances and adjustments that occur in system development, you have to have your objectives crystal clear in your mind.  If you don’t know where you are going, then any old road will do.” 

“Objectives give you the basis for making choices and prioritizing actions.  This is not to say that objectives are static.  In fact, they can change as you discover either unexpected limitations or advantages in your system as it matures.  But before you start you must have an initial set of goals and objectives to guide you.” 

Calibration:  “After the system is deployed and operational, part of the process of calibrating the system is checking to see if the objectives still fit the person or organization that you have become.  That’s a very exciting part of system design.  I can’t tell you how often I’ve been part of a design team that started with a limited set of objectives and discovered in the “imagineering” phase that by adjusting our sights we were able to accomplish far more for much less. But, you have to start somewhere.  If you don’t start with objectives, you are spinning your wheels.”

I posed this question to Ken:  “This section is critical.   How will you know if your system is working or not?  What are your performance benchmarks?  What are your criteria for knowing that your system is not working?  How will you make decisions when these criteria are met?  Will you scrap everything or just make position sizing adjustments?"  All of these questions are critical to developing and operating a good trading system.