The Right Mix

A Measure of Quality

“This porridge is too hot, this porridge is too cold, this porridge is just right”

Goldilocks knew exactly what she wanted. Even if she’d not shared her requirements with the bears beforehand.   However the measures made were fairly subjective.

Sand castle right mix
Sandcastle – Right Mix

In other situations it is much more important to get the mix right. Try building a sand castle with sand that is too wet, or too dry and the product fails, and that’s not just an opinion. If that was part of a concrete mix for a new building, you’d want to be sure it was “just right”.

What Is Quality?

Magna Carter image from national archive used under open licence
Magna Carter

What constitutes ‘quality’ will vary by product and stakeholder. Some may consider a luxury leather bound volume a ‘quality’ product. It would be wasteful and excessive to use such an expensive resource to write shopping lists. It would be more appropriate to use it to record pledges of office for city officials that will be kept in a permanent archive.

Quality may be best judged by the longevity of writing preserved in the volume’s pages. It will be of little use if its writings fade to invisibility in a few years. Copies of the Magna Carta written on parchment have lasted for over 800 years. This would be unlikely had it been written on cellulose based paper with a disposable ball point pen.

How Do You Measure It?

As part of our validation activity, we will need a way to measure the characteristics that we have decided will be used to describe quality. In our example, we could subject our ledger to an accelerated weathering simulation with cycles of varying intensities of UV light, humidity and temperature. We could then check the integrity of the volume’s bindings, its pages and the contrast of the ink and the page.

With defined quality metrics and measurable values for each metric, the quality of each product can be judged against the metrics and accepted or rejected.

What If I Can’t Measure It?

Ruler Segment - illustrating "Measure"

There are some things that are much more difficult to quantify. However that should not stop us trying. A customer requirement to have a soft-touch finish on their product could be met by covering it in foam padding, or a velvet cover. These might be acceptable for a chair, but not much use on the handle of a cold chisel. For this quality metric, the customer wanted something to absorb vibrations and so make the tool more comfortable to use. There may be measures of ‘softness’ in terms of compressibility and stiffness, but these may be difficult to use as quantities; You could argue velvet feels ‘softer’ than a rubberised plastic handle, but the latter will compress more than the former.


In some cases to make the requirement SMART (Specific, Measurable, Attainable, Realisable, Traceable) the specific and measurable aspects may be done by comparison, or actually specifying part of the ‘solution’ in the requirement. Whist well written requirements should not mandate the solution. They should be a detailed expression of the needs, allowing the design and production to choose the most appropriate solution. However, this is not always possible. “The chair must be covered in velvet“, is really a constraint, it is unambiguous and would allow the end product to be undeniably validated. However, we could still debate the “plushness” and whether it is made from artificial or natural fibre.

Be Clear

In the case of the chisel, the main product finish may be specified by meeting a design constraint; such as British Standard BS 3066. This will ensure hardness of the cutting edge impact resistance will be suitable. However, the optional handle would not be covered.

We could write, “The handle should be soft to the touch providing good grip and absorbing at least 50% of the impact force when compared to an uncovered chisel. Properties comparable to the material used on the Club hammer CLBHM002 in the same range should be considered.” This time the requirement is not mandating the same material, it is allowing practical consideration as to what is possible in the manufacturing environment. It does invoke a measurable aspect whist not needing to meet specific values. It also highlights the reasons for the specification, to provide grip. If this came to a point of discussion and the supplier covered the handle in PTFE encased foam, it may be soft but would not be considered an aid to grip. However, a rubber, or texturized plastic would both pass muster.

Strive Towards Acceptance

A cold chisel
Cold Chisel

The book on requirements management might tell you about being precise. Even in the trivial examples given we could all spot flaws. How long does the handle need to last? Does the product have to be water repellent? It would be terrible using a chisel with a lovely shock absorbing handle, if it became cold and soggy at the first sign of rain, or when rinsing it clean.

As either a customer or supplier we can mitigate against these problems, by taking a more agile approach to the whole design. Before final design and definitely before production, a round of review of design and validation criteria should be undertaken. Samples of the handle material can be shared with the customer. The baselined requirement can be updated with a new version, to explicitly state “The handle shall be manufactured from a suitably damage tolerant material, providing a good non-slip grip such as EVA – an ethylene polymer“. We have then full traceability that the requirement was updated as a result of design review. We also have a constraint that can be validated.

A Word of Caution

Whilst communicating with  potential suppliers, you also need to ensure a building of trust. Ensure each side has all the correct confidentiality agreements signed. Make sure it is clear who owns the IP on any design. Whilst researching this article, the need to keep your discussions under wraps was highlighted, by Footprint Tools. If details are handed out too freely, you may find a supplier you end up not using plus a competitor buyer,  beats you to market. Unfortunately you may also find if your chosen supplier is less than trustworthy they  could  use your design to create product for another buyer.  Quality in this case applies to the contract and the trust of everyone in the engineering lifecycle chain.


July 2021 Newsletter

Seek or Sell?

Searching internet based on pexels-ekaterina-bolovtsova-4050216
Seek / Sell

At some point or other in business we are either looking to buy or looking to sell a product or service. It’s not a simple interaction, if we are seeking we need to be able to find the product we are looking for. This could be achieved by using a trade journal or directory, or by using your favourite search engine.

However, this relies on the product having been categorised  in the way we are seeking. Take, for example, the requirement to add a visitor’s overflow car park at the office. Do you look under ‘builders‘ or ‘landscape contractor‘?  On the other hand, as a purveyor of graduated measuring tubes do we advertise under ‘medical supplies‘ or ‘laboratory equipment‘?  In truth if costs allow, placing an advert in both categories or key search words is the best option. It would likely be wasted effort placing an advert in the “injection moulding” section, even if that is actually how the product is manufactured.

User Interface

The seek or sell ethos need not be restricted to buy or sell advertising. It can be applied to usage of your product or service. Under which UI (User interface) heading will the user look to find the ‘preferences‘ setting? Should  be able to trigger a report from a ‘reports‘ menu, or from within each ‘dashboard‘? If you provide automotive repairs, should your website show ‘puncture repairs‘ under the ‘Wheels and Tyres’ menu or under ‘Repairs and Servicing‘?

When a user wants to switch on the set-top box, where do they instinctively look for the on/off switch on the remote? (Think, how often is the ⏻  Power Symbol at the top of the control, you’re unlikely to find it in the middle. To illustrate a point, if you see a strange box before the graphic icon, that’s because the rendering of the unicode character ⏻ is not supported in your browser – we thought of that and placed the graphic there too.) Design should be mindful of what and how others look, and what we provide; are we the seeker or the seller.

Survey, Testing/Monitoring, Feedback

Asking potential users, observing usage of ‘sample customers’ and allowing a route for suggestions are all ways we can tweak the efforts we place in the ‘Sell‘ side of the process to help those ‘Seeking‘ the product, facility or menu option. Online advertising tools may help identify routes taken to find, or miss a particular landing page. These can’t be applied to printed journals or directories. Observing a user, not familiar with your product, attempt to operate it, may well lead to reconsidering the positioning of controls. Lastly we should all listen to our end users and provide a method by which they can feedback, e.g. .

Training Course

Cradl;e online training course
Cradle Online Training

The public training course for July is for System Administrators; “System Administration 21st July”. Book now if you would like to reserve a place.  In August there is another chance to attend the Requirements Management course between 17th-19th August. These public courses are open to all, great if you only have a couple of people needing training, or wish to get feedback from other candidates using the product. If you want a course specific to your company or with tailored content please don’t hesitate to contact


Cradle TER module - Test Run
Test Run

In April we highlighted the new Test Execution and Recording module available in Cradle. The only sure fire way to ensure your product / service meets the agreed characteristics is to validate and verify the result. Validate the solution meets to the requested product aspect and verify that the final output matches the design. Both these steps require a plan of some description. A set of tests that can be applied to the design or product to demonstrate to the satisfaction of the stakeholders that the system is ‘up to scratch’. In the case of verification, this may be repeated on each or a sample of the project’s output. Of course it would be a bit pointless running these tests without recording the results. The Cradle TEST (Test Execution and Recording (TER)) is designed to do just that.

Social Media


Arup Tweet July 2021
Arup Tweet July 2021

We thought the digital facility from Arup of monitoring, inspection and recording to provide the best through-life support was a good way to support the customer and ensure longevity, and uninterrupted service.

We were reminded that we’d been Tweeting now for 12 years!


YouTube channel - Subscribe
Subscribe to our YouTube Channel

If you want to keep up to date with Cradle installation, instructional and feature highlight videos available  then they are available on our YouTube channel. See the play lists  and hit the “Subscribe” button.


That’s the summertime July 2021 Newsletter, stay safe, enjoy the sunshine and if you want a topic covered in our August 2021 Newsletter,  contact us at