These answers don’t seem responsive to the question as I interpret it. I think the question in fact is asking how testing can reveal specification defects. Most testing won’t, because it is reactive, simply confirming that the what the developer created conforms to the design/specification. Specification defects, whether incorrect or overlooked in the specification, are a major source of errors in the developed system, since neither the developer nor tester is likely to detect the specification defect.

Effective requirements and design reviews can reduce the number of defects in the design/specification. In addition, my Proactive Testing(tm) methodology uses a variety of powerful special test planning and design risk analysis techniques which indeed help spot many otherwise overlooked defects, most of which are overlooked because they are defects in the design/specification.

Thanks Mr. Robin for clear & concise info. I agree with you.

Here I am adding elaborated info on pro-active testing.

Pro-active testing will help prevent the specification defects and helps to be in sync with all the stakeholders regarding ‘what the final product will be & do?’.

How to do this Pro-active testing?
The tester should be pro-active to understand the product, product scope, testing scope, on-going changes in the product etc. i.e.

1. What the product is?
2. Why this product is needed? (What are the business drivers for this product?)
3. Who are the customers? How they will deploy in their environments and use?

4. When (which circumstances) this product will to be used? How many concurrent users are expected etc?

5. How the product is Architected?
How this Architecture fits for our purpose?
How different components in the product communicate?
Example: if the product is built as a strong security server then How this Architecture is providing the required security ? etc

6. What is the scope of the testing i.e.
Check whether the product requirements are Clear, Correct & Completely specified?

What makes the customer to refuse the acceptance of the product? Understand what balance of quality characteristics need to be tested in this product?

Quality characteristics can be:
Accuracy (Correctness, Completeness), Reliability, Security, Robustness (fault-tolerant), Performance (resource utilization, timeliness), Usability, and Adaptable in multiple environments etc.

Why so many Quality characteristics? Which characteristics must to have and which are nice to have?
Accuracy (Correctness, Completeness), Reliability Gives value to the product, so must to have.
And other characteristics Add Value to the Product so nice to have.

But providing only must to have characteristics will not win the market. Remember most of the products are rebuilt NOT because they are functionally deficient but because they are vulnerable (security is compromised), difficult to maintain/ port/ scale etc.

So we need to also provide the characteristics which add value.

But in competitive environment, providing all the characteristics completely in a single product is NOT feasible since it takes lot of time.

So, to win the market, we need to see what balance of quality characteristics our product is required? So discuss with your key-stake holders to identify this balance.

7. Tester should be pro-active in verification of the balance of these Quality characteristics.
What does u mean by balance of Quality characteristics?
Example: Performance Vs Reliability. Do we require Performance or Reliability?

If we want to improve the performance of the product in I/O activities then we may prefer to have Cache in between. The cache will helps in reducing the IO activities since the data will be transferred to the database once in a while.

But what happens if we lose the cached data (due to power failure etc) just before transferring to the database? the product reliablity is lost right.

So one characteristic is affecting the other characteristic. i.e, providing performance is affecting the reliability of the product. And you know if reliability is lost then the market for the product is lost.

So, to increase the Performance and at the same time maintaining Reliability requires the balance of these 2 characteristics in the product design.

7. What are the 3rd party tools used? What are their limitations? Are they affecting the balance of Quality etc?
8. It is Tester’s responsibility to make sure all the stakeholders are in sync with ‘What the final product will be & do?’ i.e., the required requirements, plan, design, implementation etc. For this participate pro-actively in reviews, writing test cases, expected output etc at each phase of the product.

What do you think? Any thing to add?