Comparing Traditional Approaches to Experimental Design

The traditional approach taken to develop a new process is One Factor at a Time (OFAT) (Figure 1). Experimental design, on the other hand, is a structured set of tests of a process to investigate potentially significant factors that helps to establish cause and effect relationship on the output (Figure 2) The advantages and disadvantages of both approaches are discussed in Table 1 and Table 2 below.

Figure 1: One Factor at a Time (OFAT) approach — **Figure 1:** One Factor at a Time (OFAT) approach

Table 1: Advantages and disadvantages of the OFAT approach
Advantages	Disadvantages
Widely taught	Limited coverage of the experimental space
Straightforward	May miss the optimal solution
	Fails to identify interactions
	Inefficient use of resources

Table 2: Advantages and disadvantages of the DoE approach
Advantages	Disadvantages
Systematic: Thorough coverage of experimental “space”	Minimum entry of ca. 10 experiments
Efficient: Able to establish solution with minimal resource	You may have to run experiments that you anticipate will “fail”