Types of Product Design Reviews


A design review does not require the physical product, as long as there is sufficient data from the manufacturers, testers, expert sources, etc. The value of reviewing compiled design data is as good as the value of reviewing a physical product. One is focused on the design specs while the other is focused on usage. 

What is a review?

  • To look at or examine (something) carefully especially before making a decision or judgment. (dictionary)
  • A report that gives someone’s opinion about the quality of a book, performance, product, etc.

The “something” can be anything, from a physical item to data or written documents. The deliverable can be a report, a decision (verdict), opinion, recommendation or judgement.

Product Design Reviews

Formal product design reviews are key milestones within a formal product development project whereby a design is evaluated against its requirements before moving on to the next sub-phase. A successful design review will be followed by a product launch or release.

There are also “informal” design reviews that are performed before a purchase, where potential buyers will perform research and review on product design and specifications, other expert opinions, or sample test reviews. In recent years, there was increasing popularity in “unboxing” reviews where “reviewers” will open up a new box of products on video.

For products that have been in the market for some time, there will also be user experience feedback especially on the shopping site, in the form of “product review”.

In any case, a design review does not require the physical product, as long as there is sufficient data from the manufacturers, testers, expert sources, etc. The value of reviewing compiled design data is as good as the value of reviewing a physical product. One is focused on the design specs while the other is focused on usage.

Phase 1: Product Development Stage (Within a business)

The first phase occurs within the company that design and manufactures the product. The design reviews are performed in-house by project team members, stakeholders and may include others such as production leaders.

The design reviews may include several sub-phases such as preliminary (PDR), critical (CDR), and final (FDR) design reviews. During the review, members will assess if the prototype design is acceptable and has met the design intent and target specifications.

After the product design is final, and mass production begins, the company will produce marketing material to attract buyers to purchase their product.

Phase 2: Product Buying Stage (Between business and consumer)

In this phase, potential customers, product reviewers, or purchasing specialists will source products to meet their needs. The process normally involves identifying at least 3 competing products that are potential alternatives for in-depth review.

The review will compare the design specifications and prices to determine the most cost-effective option. If the order is large, the reviewer may acquire one or more samples to try out before deciding which one to order.

  • For a newly launched product, which we do not have a sample on hand:

    • Expert decision: You can become an expert in a chosen niche product category and perform product design reviews.
    • Research work: You can be a product researcher to compile, compare and review the information to deliver an unbiased verdict on the product. Such design review may also discuss the technology, alternative solutions, previous product versions, or other possibilities.
  • For a newly launched product, with a sample on hand:

    • Early Tester: Such product reviews are performed by selected “Early Tester” who have the chance to get the product.
    • As there is an actual product on hand, the review should focus 100% on the user experience because you are the eyes, ears and hands of the readers who cannot touch the product.
    • Such reviews do not require extensive research or expert involvement, even though these abilities may help for complex products.
  • For products already in the market for some time, which we do not have a sample on hand:

    • Sieve through thousands of user feedback to summarise the important feedback.
    • Read through expert reviews to summarise the key points.
    • Some product review blogs on sports shoes posted reviews based on summarising other user’s feedback. This is an excellent way to add value for readers so that they do not have to go through thousands of “product reviews” to look for informative comments.

Phase 3: Product Feedback Stage (Consumer only)

After buying and using the products, the buyer may provide feedback on the usage which may be related to the function, durability, reliability, etc. All of this feedback ultimately affects the design, which will then be feedback to Phase 1 for the next product development phase.

In shopping websites such as Amazon, Taobao and Shopee, there are thousands of user feedback which they call product “reviews”. However, out of the thousands or millions of feedback in the shopping system, there are only a handful of comments that are really useful.

Sometimes the shopping sites provide incentives for the buyers to leave a comment, so they are written because of the perks. Most of the time, we would read the bad comments to make sure there are no systemic problem.

For example, say if 30% of 1,000 buyers give a 1-star rating that a product stopped working within one week of using, we will not bother reading 70% of the “good” 5-stars reviews.

Below is a summary of the different design reviews in the three phases of the product life cycle.

Phase 1:
Product Development
Project Team.
Prototype Team.
Production Team.
Stake Holders
Customer inputs.

Market data.
Target specs.

Product design.
Prototype production and testing.
Design Reviews:
– Preliminary
– Critical
– Final
Final approved design for mass production.
Phase 2:
Sales Phase
External Purchaser.
Product reviewer.

End User.
  • Research 
  • Tech specs.
  • Other user’s feedback (from Phase 3)
  • Test samples (if available)
  • Test videos (Youtube)
Review design based on
– Pros/Cons
– Compare Alternatives
– Desired Specs
– Technology
– Challenges
– Achievements/Awards
Decision to buy
Phase 3:
Feedback Phase
Confirmed buyerReal user experience– Shopping review
– Forum feedback (e.g. Reddit)
– Social media feedback

The above covers the Type of Design Reviews in the context of the generic product life cycle.




Below are old notes for sharing only. They are not organised and will be updated later.

During the prototyping stage, designers and engineers will perform design reviews to compare the design against the target specifications.

When sourcing for products, a common practice is to check up existing user reviews for products that have been around for some time.

But for newly launched products, the reviewer has to find a sample to try out, or simply perform a review of the design specifications if it is not possible to get all the samples. In fact, such a review without the actual sample is tedious and requires a detailed examination (See “review” definition above) of the available information.

Some products require experts who are technically competent to review the technical specifications and product design, such as buying a professional CNC machine.

We also cannot depend on other user’s feedback for certain products that require a good fit. For example, we recommend buyers try out wireless earbuds and earphones samples before buying to make sure that they fit snugly.

Last but not least, buyers who have purchased the products can feedback on their experience in the form of a “product review“, such as those posted in the online stores. These are actually user feedback based on actual usage, and not really a “review” which as said above is to examine closely and carefully.

Among the thousands of reviewers, there are very few who can write really good and informative reviews because it takes time and effort. Most of the time reviews are short and straight to the point (i.e. good or bad), or rants, or irrelevant comments.

Product Development Projects

Product development projects began with a concept idea of the new product, which may include design sketches, CAD drawings, and a rough list of desired specifications.

This is followed by feasibility studies to ascertain if the target specs are achievable based on current resources and technology, or require additional cost, effort, and time to develop new capabilities. The output of this stage will include the project scope, schedule, and budget.

Design reviews are the key milestones in a product development project. It involves formal meetings, and acceptance tests conducted to verify that the prototype(s) in various development phases have each met the target design specifications.

As the prototypes may need to undergo several design changes and rework before being accepted, the design review can be broken up into three key phases to reduce project risks such as loss of time, resources, or financial losses.

The following are the phases and types of design reviews in product development.

During Product Development

Product design reviews can only be conducted by the project team members.

1. Preliminary Design Reviews (PDR)

    • Components prototype
    • Mockup of a full or partial assembly

If the prototypes and components are rejected or need a rework, there may be a need to redo the PDR or have a PDR II.

2. Critical Design Reviews (CDR)

    • The pre-final or beta version of the final product shall undergo an acceptance test to verify all critical design specs against the target specs.
    • There should be very few minor changes required to finalize the product.

3. Final Design Reviews (FDR)

    • If required, a final design review is conducted to verify any corrective actions made during the CDR.
    • After the FDR is completed, the product is ready for serial production and rollout or released.

After Product Rollout

Post Implementation Design Reviews

    • The project team should conduct frequent PIDR reviews after the completion of the project. During the reviews, the project team shall discuss the issues raised from the following areas:
      • Warranty claim
      • Customer support team
      • Problems raised by user reviews and feedback from websites, online stores and blogs.
    • Identify each of the problems raised.
    • Identify the cause and effect of the problem via FMEA (Failure Mode and Effects Analysis)
      • Are they design issues? If yes, the designers will need to review the remedy actions.
      • Are they quality issues? If yes, the manufacturing dept. will need to review their IPQC process.
      • Are the effects critical, or safety-related? If yes, there could be a need to recall the affected batches or all the products.

The above are brief examples of types of design reviews at each project phase.

In addition, we believe that everyone is performing design reviews every time they are buying a product.

For example, most users will not just pick a car, pay and drive. They perform their own “design review” of the cars before they “proceed” to the next phase.

They will look at the car’s exterior and interior design, check the specifications, and perform a test drive (acceptance test) to decide whether it meets their fickle-minded, ever-shifting requirements hidden deep inside their head. This is also a type of “design review” and is also affected by emotions and value.


The project is about scope, schedule, and budget, which are all interrelated. For example, an increase in scope may cause a delay in schedule and an increase in budget. In another example, if the budget is cut down, the scope may be reduced but the duration of the project may go either way.

The most common factors affecting buying decisions are function, value, and emotions. The dominant factor will depend on whether the buyer is the user himself or for someone else.

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