A defining kind of thinking that designers do repeatedly involves balancing the benefits and drawbacks (tradeoffs) of different approaches to reach a preferred solution. Having students talk and write about the tradeoffs they are considering when deciding on one prototype among others can help them get better at doing informed designing.
"One of the most difficult aspects of product development is recognizing, understanding, and managing such tradeoffs in a way that maximizes the success of the product." Karl Ulrich and Steven Eppinger Product Design and Development (1995).
Tradeoffs are described in AAAS' Atlas of Science Literacy as a central tenet to design reasoning. Sometimes Decision Grids (see page 6 of LBD's Design Diary) can visually depict the benefits and tradeoffs of an especially difficult design decision among competing design ideas. The following are cases where tradeoffs play a role in making design decisions:
- Air Quality/Home Heating - In winter, all houses leak heated air to the outdoors. Methods for sealing homes that limit such air transfer have gotten so good that houses are "too tight". Such houses have the benefit of losing little heated air, but suffer the tradeoff that occupants to get sick for lack of fresh air.
- Gloves: One-Size-Fits-All/Goodness-of-Fit - It costs less to make one-size-fits-all gloves, but for a number of users, the fit is poor.
- Optimal Popcorn Cooking Time - During the first two minutes of cooking popcorn, most of the corn pops. You can continue to cook so that 100% of the kernels pop, but risk the tradeoff of burning the existing popcorn.
- Cost/Benefit: Titanium Cellphone - You can use strong-yet-light material like titanium to make a cellphone that does not break when stepped on, but the tradeoff is that the phone will cost as much as a laptop computer.
- Flat Roofed House: Easy-to-build/Hard-to-maintain - A house with a flat roof is easier to build that one with a sloped roof. When it rains, however, flat roofs have problems with water collecting and leaking inside. Maintaining a flat roof requires extra work that a sloped roof does not require.
- City Planning: Casinos in Town - Those who wanted casinos in Atlantic City, NJ, argued that the benefits of increasing business and state tax revenues in the New Jersey shoretown would outweight the tradeoffs of increased crime and a reduction of gambler's spendable income. As the Atlantic City Journal reported in May 25, 2003, "The [gaming] industry has changed the face of Atlantic City with new residents, new development and new problems."