MS-ETS1-2: Evaluating Competing Designs
Also called NGSS MS-ETS1-2 · Topic: Engineering Design · Engineering, Technology, and Applications of Science
The Official Wording
Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What MS-ETS1-2 Means in Plain English
Students judge several possible solutions to the same problem with a fair, step-by-step method instead of a gut feeling. They test or rate each design against every criterion and constraint, often in a decision matrix, and pick the design that meets the most important needs best.
The winner is the best fit for this problem's criteria, not a perfect design. This builds on defining the problem (MS-ETS1-1) and leads to combining the best features of several designs (MS-ETS1-3).
MS-ETS1-2 I Can Statements
- I can test each design against the same criteria.
- I can use a weighted decision matrix to compare designs.
- I can explain why one design fits the problem best.
MS-ETS1-2 Worked Example
Three teams built different wheels for a cardboard model rover, and the class scores all three with the same tests.
Which wheel design best lets our model rover cross loose sand while carrying its load?
Set It Up: A cardboard rover body, three wheel sets (bottle caps, cardboard paddle wheels, wide foam rings), a tub of dry sand, a 200 g payload and a budget sheet.
- Agree on criteria and weights before any testing.Sand crossing ×3, carries 200 g ×2, cost ×1, build time ×1
- Run each rover across 50 cm of sand three times with the payload.Bottle caps sink, paddles cross every time
- Score each design from 1 to 5 on every criterion.Caps 1, 4, 5, 5. Paddles 5, 3, 4, 2. Foam 4, 4, 2, 3
- Multiply each score by its weight and add the results.Caps 21, Paddles 27, Foam 25
- Check the total against the most important criterion.Paddles win and also scored highest on sand
The paddle wheels scored 27, beating foam at 25 and bottle caps at 21, mainly because they crossed sand reliably, the most heavily weighted criterion.
Why it works: Wide paddles spread the rover's weight over more sand and push against it, so they sink less and grip better than small, smooth wheels.
Common Mistakes with MS-ETS1-2
Picking a favorite before testing
“The foam wheels look the coolest, so they win.”
Try this: Set the criteria and weights first, then score every design the same way, so the data decide instead of looks.
Weighting every criterion the same
Build time counts as much as crossing the sand
Try this: Give the criteria that matter most bigger weights. A rover that can't cross sand fails, however quick it was to build.
Testing designs under different conditions
One rover runs on packed sand, another on loose sand
Try this: Use the same track, payload and number of trials for every design so the only difference is the design itself.
Where MS-ETS1-2 Fits
Practice MS-ETS1-2
Quick Check
- Why decide the weights before testing?
- Design X scores 4 on a criterion weighted ×3. How many points does it earn there?
- Does the top score mean the design is perfect?