According to the definition of Rolled Throughput Yield which of these items best describe the purpose of RTY?

Rolled Throughput Yield (RTY) is a key Six Sigma metric that measures the probability of a unit passing through a multi-step process without any defects, scrap, or rework on the first attempt. It is calculated by multiplying the First-Time Yield (FTY) of each individual process step. Unlike final yield, which only considers the final count of good units, RTY provides a more accurate assessment of process efficiency by explicitly accounting for the "hidden factory"—the resources and effort consumed by rework and the losses incurred from scrap at every stage of the process.

A. A function of Y=f(x): This is the general Six Sigma model describing the relationship between process outputs (Y) and inputs (x), not the specific purpose of the RTY metric.
C. Isolates the increase throughput: RTY measures process yield, not throughput (production rate). While improving RTY often leads to increased throughput, its primary function is to quantify defect-free output.
D. Determines incremental Growth: This is too vague. RTY is a performance metric that can be used to track improvements over time, but its fundamental purpose is to measure process yield, not to "determine growth."

1. Pyzdek, T., & Keller, P. A. (2018). The Six Sigma Handbook (5th ed.). McGraw-Hill Education. In Chapter 15, "Measuring Process Performance," the authors define Rolled Throughput Yield as the product of the yields of each step in a process. They explicitly state, "The advantage of RTY is that it includes the impact of rework... RTY provides a realistic estimate of the cumulative effect of problems in a process." (Section on Rolled Throughput Yield).

2. Antony, J., & Banuelas, R. (2002). Key ingredients for the effective implementation of Six Sigma program. Measuring Business Excellence, 6(4), 20-27. https://doi.org/10.1108/13683040210451679. On page 24, the article defines RTY as "the probability of a product or service passing through the entire process defect-free," which inherently includes avoiding rework and scrap.

3. Montgomery, D. C. (2013). Introduction to Statistical Quality Control (7th ed.). John Wiley & Sons. In Chapter 1, "Quality Improvement in the Modern Business Environment," Section 1-4.3, Montgomery discusses process yield and notes that Rolled Throughput Yield provides a cumulative defect measure for a series of process steps, highlighting its role in identifying losses that traditional final yield metrics would miss.