Criteria and Constraints

Criteria and Constraints

Middle School

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Learning Objectives

• Define what criteria and constraints are in the design process.

• Differentiate between a requirement (criterion) and a limitation (constraint).

• Explain why identifying criteria and constraints is a crucial first step in solving a problem.

• Analyze given scenarios to identify the criteria and constraints of a design solution.

Key Vocabulary

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Criteria

The specific requirements and standards a design solution must meet in order to be successful.

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Constraints

The limitations or restrictions you must consider when designing a solution, such as time or cost.

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Design Process

A series of steps that are followed to come up with a solution to a problem.

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Defining the Problem

• The first step in a design challenge is to define the problem.

• You must also figure out the main goal you want to achieve.

• Identify the criteria, or the requirements for your solution to be successful.

• Consider the constraints, which are the limitations you must work within.

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Multiple Choice

During which phase of the design process must you first identify the criteria and constraints?

• In the 'Define problem and goal' phase

• After testing the solution

• When choosing materials

• When building the solution

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What Are Criteria?

• Criteria are requirements a design must meet to be successful.

• They list what the design needs to do to solve the problem.

• Think of criteria as a checklist for a successful design solution.

• For example, a criterion could be that fish are collected unharmed.

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Multiple Choice

Based on the slide, what is the best definition of criteria?

• Requirements the design must meet to be successful

• Limitations like time and money

• Optional suggestions for the design

• The final step in the design process

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What Are Constraints?

• Constraints are the limitations or challenges you must work within for a project.

• ​Your design solution must always stay within the project's set constraints.

• Common constraints include limits on time, available budget, and necessary project materials.

• Scientific laws, like how deep a scuba diver can go, are also constraints.

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Multiple Choice

Which of the following is an example of a constraint?

• The solution should be easy to use

• The solution needs to help students

• The design must be painted blue

• A limited budget for materials

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Common Misconceptions

Misconception	Correction
Criteria are just optional suggestions.	Criteria are essential requirements a solution must meet.
You can ignore constraints if your idea is good.	All solutions must work within the given constraints.
Criteria and constraints are the same thing.	Criteria are requirements, while constraints are limits.

Multiple Choice

How do criteria and constraints guide the process of choosing a solution?

• A successful solution must meet the criteria while staying within the constraints.

• They are considered only after a solution is built to see if it works.

• Criteria determine the budget, while constraints determine the features.

• Constraints are more important than criteria when choosing a solution.

Multiple Choice

A company wants to create a new water bottle. Why is it important for them to identify the criteria (e.g., it must not leak) and constraints (e.g., it must be made from recycled plastic) at the beginning of the process?

• To ensure the final product is successful and achievable within their limits.

• To slow down the design process.

• To create a marketing plan for the new bottle.

• To order the materials before designing the bottle.

Multiple Choice

An engineer is designing a new bridge. The city requires that it must support four lanes of traffic and last for 50 years. However, the project has a limited budget of $10 million. Analyze these factors.

• The budget is a criterion, and the traffic lanes are a constraint.

• The traffic lanes and 50-year lifespan are criteria; the budget is a constraint.

• The 50-year lifespan and the budget are both criteria.

• The traffic lanes are a criterion; the budget and lifespan are constraints.

Multiple Choice

Imagine a team designs a revolutionary new fishing net that can catch fish from the twilight zone unharmed (meeting a key criterion). However, the net is so expensive to produce that no one can afford it (failing a cost constraint). Predict the most likely outcome for this solution.

• The solution will be a huge success because it meets the most important criterion.

• The solution will be considered a failure because it is not viable within its real-world constraints.

• The team will ignore the cost constraint because the technology is so advanced.

• The criteria will be changed to match the high cost of the solution.

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Summary

• Criteria tell you what a successful solution must be able to do.

• Constraints are limits like time or money that you must work within.

• Identifying criteria and constraints is the first step of the design process.

• A good solution meets all criteria while following all constraints.

Poll

On a scale of 1-4, how confident are you about differentiating between criteria and constraints?

• 1

• 2

• 3

• 4