Why did we include ExpressionEvaluator_2001 in the custom transformer but not ExpressionEvaluator_2011?

Why did we include ExpressionEvaluator_2001 in the custom transformer but not ExpressionEvaluator_2011?

• A. Custom transformers can only include one of each type of transformer.
• B. Including both would cause a divide by zero error.
• C. Including both would create performance issues.
• D. We will eventually create a generic custom transformer we can reuse to calculate the 2011 population density as well.

Answer: (D)

The idea being tested is how to design a custom transformer for reuse across similar tasks, rather than hard-coding separate components for each year. By making the calculation logic generic and parameterized, you can apply the same transformer to different years (like 2001 and 2011) without duplicating the wiring or logic. Including the 2001 expression evaluator captures the current calculation, but withholding the 2011 evaluator signals an intention to generalize. When you build a single, generic custom transformer that accepts a year or related field as a parameter, you can reuse the same logic for 2011 by simply changing the parameter, keeping behavior consistent and reducing maintenance. Other options are less fitting because they imply constraints or issues that aren’t the root goal here. The emphasis is not on limiting the number of transformers or avoiding a specific error; it’s on creating a reusable, configurable component that can handle multiple years. DGives the clearest path to future reuse by design.

The idea being tested is how to design a custom transformer for reuse across similar tasks, rather than hard-coding separate components for each year. By making the calculation logic generic and parameterized, you can apply the same transformer to different years (like 2001 and 2011) without duplicating the wiring or logic.

Including the 2001 expression evaluator captures the current calculation, but withholding the 2011 evaluator signals an intention to generalize. When you build a single, generic custom transformer that accepts a year or related field as a parameter, you can reuse the same logic for 2011 by simply changing the parameter, keeping behavior consistent and reducing maintenance.

Other options are less fitting because they imply constraints or issues that aren’t the root goal here. The emphasis is not on limiting the number of transformers or avoiding a specific error; it’s on creating a reusable, configurable component that can handle multiple years. DGives the clearest path to future reuse by design.