Why there is no perfect design

no perfect design

Design always involves choices within a set of constraints and has compromise as its essential characteristic. Everything that is designed is a result of a series of negotiations between materials, manufacturing methods, time, and money. Functional design and user experience can create tension as can price and performance goals.

Small Things Considered: Why There Is No Perfect Design by Henry Petroski


In Small Things Considered, Henry Petroski discusses the design history and context for drinking cups, chairs, paper bags, stairs, supermarket aisles, flashlights, toothbrushes, and many other common artifacts. Petroski’s book is about the myriad small, large and often hidden decisions and parameters that affect an overall product, service, building, or experience design. Petroski writes about a wide range of designed objects, environments and experiences and highlights both their history as well as the nuance of choices that were made to create the final product. For example, he describes the complex and interrelated decisions he and his wife went through to remodel their home.

There are a multitude of design decisions that surround us. What be should the distance between a doorknob and wall or door frame? Why are doorknobs and light switches at different heights? Why is there no standard placement of light switches in public places like hotel rooms? Design choices resulting historical constraints can turn into building codes and storage standards (like a standard toothbrush holder which cannot accommodate a newer, larger, ergonomically designed toothbrush grip).

Designing anything…involved satisfying constraints, making choices, containing costs, and accepting compromises…Constraints are typically a major part of the defining features of a design problem, and so they become dissolved and absorbed into the solution.

Petroski’s reflections on objects contain several themes related to choice, constraints, and compromise. Each chapter in the book dissects one object or category of object. He interleaves personal experiences such as the drinkholder in his car and his house remodel.

Design is embedded in a context of constraints

…the primary purpose of most things is to perform a function, and because the goals of aesthetics, user friendliness, and doing a job effectively can be in conflict, economics often becomes the referee. The design process is characterized mostly by tensions between competing objectives that are resolved by compromises, usually driven by manufacturing cost and sales price.

Because every design must satisfy competing objectives, there necessarily has to be some compromise among, if not the complete exclusion of, some of those objectives, in order to meet what are considered the most important of them.

The decision maker has a choice between optimal decisions for an imaginary simplified world or decisions that are ‘good enough,’ that satisfice, for a world approximating the complex real one more closely.

Petroski observes that “Designing without constraint would be like playing baseball without fences or foul lines.” There are many types of constraints with which a designer must contend: space, energy consumption, material characteristics. A printer cartridge must be designed to function inside a printer, a printer to fit inside a box, and a print cartridge to fit inside a printer and a package box. Cars must fit on a train, a ship, within parking spaces and road lanes. Materials create constraints due to strength, durability, and temperature tolerances. As Petroski notes, time and money frequently impinge on the possible design options under consideration. To illustrate the point, he discusses the design of the cupholder in his Volvo which was retrofitted into the cars after cupholders became popular in the US. The cupholder is contained in the top of the center console storage unit and to the left of the manual parking brake. It’s interesting to think about all the options for placing the cupholder in the car–Petroski discusses many of the alternatives and considerations. He also notes that cup holders became popular in the US as a result of drive-in theatres and restaurants, which are not constraints, but form the cultural context for the design.

 Perfection is not achievable

It is telling that the titles of so many patents…begin with the words ‘Improvement in’

It is not possible to define perfection because there are too many possible goals, uses, and users for any given object or environment. Every designed object has have evolved and been improved upon by several generations of inventors, designers, and fabricators who bring to it their unique perspective. To illustrate, he gives the history of WD-40 and duct tape, both of which evolved to their ubiquitous position through a long journey. Every improvement moves the design forward and each iteration provides a new vista from which further optimization is possible.

We design everything, all the time

There is barely anything that we do, much less use, that does not have a design component to it. We design an evening before the television set.

We design our homes, our rooms, our dinners, our evenings, our routes to and from work and school. All human activity which involves creating, managing, and changing our environments involves some degree of design. Some designs specifications are institutionalized as building codes while others are cultural norms like menu layouts. Petroski discusses the design of supermarkets and toll booths in a chapter on traffic flow design.

All designs are flawed, not bad

Even though no design can be perfect, that does not mean that every design is a failure. We evaluate designs not against absolutes but against each other.

Knowing the imperfections of an object does not diminish it but, rather, can elevate the appreciation of the creative achievement that has minimized the intrusion of flaws into the design.

Because all designs involve tradeoffs and unintended consequences, something will be left out or partially implemented. Petroski tells the story of the Maglite, known for its durability and intense light beam. However, the Maglite company did not conquer the dark spot in the center of the beam and the sons of the founder created a new company which attempted to resolve that specific design issue. Another interesting example Petroski spends some time on is the fact that cell phone numeric keypads are completely different than calculator keypads. He points out the various design threads which created the divergent designs. Teflon, when used in kitchenware, is difficult to bond to surfaces and is susceptible to damage from cleaning implements.

Design is seeing beyond the obvious

Design is seeing the potential for a Halloween mask in a paper bag, the makings of a quilt in a chest of remnants, or a good meal in a refrigerator full of leftovers

Successful design can be inspired by loosely connected or unrelated ideas. Many people have observed that innovation frequently occurs at the intersection of wholly unrelated fields and industries. When seemingly unrelated ideas are brought together, their juxtaposition can stimulate new connections and combinations. The boundaries and borders of complementary fields are fertile grounds for innovation.

Petroski gives the example of IDEO’s Tech Box, a physical database of materials and inspirational ideas. He highlights the concept of a “Theatre of Machines“, a book which lists possible mechanical solutions and components which can be combined to form larger solutions and machines (for example, see Jacques Besson’s Book of Mathematical and Mechanical Instruments).

The consequences of all design choices are unknowable

 Virtually every design will be used by people other than those who created it, will exist in a context of ever-changing fashion and fad and other designs, and may potentially be shared and so not put back the way it was found.

Because designers look so closely at the thing they are designing, they can tend to see its ultimate context…as a great peripheral blur, if they see it at all.

For every design choice, there may be an equal and opposite reaction from the users of the design. It is not possible to understand the ultimate consequence of every decision that is made in the course of creating a new product, environment, or service.


In the video below, Petroski discusses engineering in the context of human advancement and points out that often engineering accomplishments like the steam engine precede scientific understanding (in this case thermodynamics). He touches on interdisciplinary design in the case of London’s Millennium Bridge, which he says was initially designed with an aesthetic priority that neglected an engineering requirement (stability from intersecting support beams).


Small Things Considered: Why There Is No Perfect Design


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