In plain English: MS-ETS1-2 is the NGSS middle school engineering performance expectation that asks students to evaluate competing design solutions with a systematic process to find how well each meets the criteria and constraints of the problem. Students screen designs against constraints, score test results on scales set in advance, and compare totals in a decision matrix. It is usually taught inside grades 6-8 science.
Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.
Next Generation Science Standards · Disciplinary Core Idea: Engineering Design · Official standard
When a team has several possible designs for the same problem, it needs a fair way to choose. These are competing design solutions: different designs that all try to solve one problem. A systematic process judges every design by the same steps, the same criteria and the same tests, in an order decided before the results are known. Recall that a criterion is something a solution must do to succeed and a constraint is a limit, such as cost or safety (MS-ETS1-1). In this lesson, students use four tools in order: screening (removing any design that breaks a constraint), a scoring scale (a rule, set before testing, that turns each test result into points), a decision matrix (a table with designs in the rows, criteria in the columns and scores in the cells) with optional weights (numbers that make the most important criteria count more), and a Pugh chart, which compares each design with one reference design using better (+), same (0) and worse (-). The goal is not just a winner but an explanation of how well each design meets the criteria and constraints, including its trade-offs: what it gives up to do well somewhere else.
NGSS gives no Clarification Statement and no Assessment Boundary for MS-ETS1-2, so the lesson follows the wording of the performance expectation. All test results, prices and scores on this page are invented for teaching and labeled as invented. The foil boat test uses tap water and pennies only.
Learning Objectives
By the end of this lesson, students will be able to:
Screen competing designs by removing any design that breaks a constraint
Write a scoring scale before testing and use it to turn test data into scores
Build a decision matrix with equal or justified weights and use the totals to compare designs
Compare designs with a reference design using a Pugh chart
Explain how well each design meets the criteria and constraints, name its trade-offs, and spot unfair steps in an evaluation
Prior Knowledge Required
Students should already be comfortable with:
Writing precise criteria and constraints for a design problem MS-ETS1-1
Comparing several possible solutions by how well each is likely to meet the criteria and constraints (3-5-ETS1-2)
Fair tests that change one variable and keep the others the same
Show three backpacks (or pictures): a cheap one, a sturdy one with many pockets, and a light one. Ask students to pick the best and to raise hands. Then ask a few students why they chose theirs.
Warm-Up Prompt
"Different people picked different backpacks. Were they using the same rules to decide? Write a fairer way the class could choose one backpack for a 3-day field trip."
Collect ideas. Students often suggest listing what matters (cost, weight, room) and scoring each backpack. Point out that this is what engineers do, and that the order of the steps matters: the rules come first, then the testing.
Direct Instruction15-20 minutes
A systematic evaluation, step by step. Define competing designs, systematic process, screening, scoring scale, decision matrix, weight, Pugh chart and trade-off (see the overview), and show Diagram 1. Then work through one problem with the class. The school garden's lettuce seedlings keep getting eaten by rabbits. Four designs compete: a chicken-wire fence, mesh row covers (net tunnels over each row), raised beds 60 cm tall, and a motion-activated sprinkler. The budget constraint is $150. Each design was tried on 50 seedlings for two weeks (invented data, Diagram 2).
Step 1: screen with the constraints
Costs: fence $120, row covers $60, raised beds $260, sprinkler $45. The constraint is a budget of $150. All four designs are safe for students to use.
Result: The raised beds cost $260, more than $150, so they are screened out, however well they work. The fence, the row covers and the sprinkler move on. A design that breaks a constraint cannot win on points.
Step 2: score survival on a scale set before testing
Before the trial, the class agreed: 3 points if 90% or more of the seedlings survive, 2 points for 80-89%, 1 point for 70-79%, 0 points below 70%. Survivors out of 50: fence 46, row covers 44, sprinkler 35.
Result: Fence 46 ÷ 50 = 92%, so 3 points. Row covers 44 ÷ 50 = 88%, so 2 points. Sprinkler 35 ÷ 50 = 70%, exactly on the edge of the 70-79% band, so 1 point. Writing the scale first means nobody can bend it to favor a design.
Step 3: build a decision matrix with equal weights
Other criteria, each scored 0-3 on scales set in advance: easy access for weeding (fence 2, row covers 1, sprinkler 3), cost (fence 1, row covers 2, sprinkler 3), and no harm to wildlife (fence 3, row covers 1 because loose netting can tangle birds, sprinkler 2 because it uses extra water).
Result: Totals: fence 3 + 2 + 1 + 3 = 9, row covers 2 + 1 + 2 + 1 = 6, sprinkler 1 + 3 + 3 + 2 = 9. The fence and the sprinkler tie, so equal weights do not settle the choice.
Step 4: weight the top priority
The problem is rabbits eating seedlings, so the class agrees, before looking at the totals again, that survival counts 3 times as much as each other criterion.
Result: Weighted totals: fence 3 × 3 + 2 + 1 + 3 = 15, row covers 2 × 3 + 1 + 2 + 1 = 10, sprinkler 1 × 3 + 3 + 3 + 2 = 11. The fence wins. Its trade-off: it costs the most of the three, and the gate makes weeding a little slower than with the sprinkler.
A second tool: a Pugh chart
The class uses the fence as the reference design and compares the other two with it, criterion by criterion: + (better), 0 (same) or - (worse). Row covers: survival -, access -, cost +, wildlife -. Sprinkler: survival -, access +, cost +, wildlife -.
Result: Row covers: 1 plus and 3 minuses, a total of -2. Sprinkler: 2 pluses and 2 minuses, a total of 0. Neither beats the reference, and the chart shows where each one is better (cost) and worse (survival). A Pugh chart shows direction, not size, so a close call still needs the test numbers.
After each step, ask: "Was this step decided before or after we saw the results? Would a different team get the same answer?" Stress that the screen comes first, that scales and weights are fixed before scoring, and that the final answer explains trade-offs instead of naming a winner only.
Guided Practice15 minutes
Pairs evaluate four designs for hooks to hang backpacks in a hallway. Constraints: each hook costs no more than $2.00 and has no sharp edges (all four pass the edge check). Criterion: a hook must hold at least 8 kg. Invented test data:
Invented test data for four backpack hook designs
Design
Load before slipping (kg)
Cost per hook
Time to install (min)
A: metal S-hook
15
$1.50
1
B: 3D-printed hook
6
$0.80
2
C: wooden peg
20
$2.40
8
D: adhesive hook
9
$1.20
1
Screen with the constraints. Which design costs too much? Which design fails the 8 kg criterion?
Score the designs that are left with these scales, set in advance. Strength: 3 points for 15 kg or more, 2 points for 10-14 kg, 1 point for 8-9 kg. Cost: 3 points for $1.00 or less, 2 points for $1.01-$1.50, 1 point for $1.51-$2.00. Install time: 3 points for 1 minute, 2 points for 2-4 minutes, 1 point for 5 minutes or more.
Add each design's scores. Which design comes out ahead, and by how much?
Write two sentences: one that says how well the leading design meets the criteria and constraints, and one that names a trade-off.
Independent Practice10-15 minutes
Each student critiques another team's evaluation of three designs for a library book drop box. Constraint: it must fit through a 75 cm doorway. The team's notes (invented):
"We tested how many books each box holds. Box 1 holds 60, Box 2 holds 85, Box 3 holds 70."
"Box 2 is 90 cm wide, but it was our favorite."
"After testing, we decided capacity is worth triple points, because Box 2 did best on capacity."
"We tested Box 3 with paperback books and the others with hardcover books."
"Final pick: Box 2."
Students name every step that is not systematic, explain why it matters, and write a corrected plan for the evaluation. They should find a broken constraint, a weight chosen after seeing the results, and an unfair test.
Closure5 minutes
Exit ticket: "Two designs tie in a decision matrix. Name two things a team could do next that keep the evaluation systematic." Return to the warm-up and ask how the backpack vote would change if the class had screened, scored and weighted first.
Teacher note: MS-ETS1-2 is about evaluating designs, so the foil boat test produces data for the matrix rather than a contest winner. Combining the best features of several designs into a new one is the focus of MS-ETS1-3.
Differentiation Strategies
For Struggling Students
Give a decision matrix template with the criteria already in the columns and a blank row for each design, plus the scale printed under each column
Start with only two designs and two criteria, then add one design and one criterion at a time
Use a checklist for every step: "Did we decide this before testing? Did every design get the same test?"
For Advanced Students
Ask students to change one weight and find the smallest weight that changes the winner, then explain whether the result is a close call
Have students design a scale for a criterion that is hard to measure, such as "looks good", using a class survey
Ask students to compare the decision matrix and the Pugh chart for the same designs and explain when each tool is more useful
Assessment Guidance
What to Look For
Check that students screen out any design that breaks a constraint before scoring, and that they apply scales exactly as written, including results that fall on a boundary. Look for weights that are justified by the problem, not by which design they favor. Strong answers explain how well each design meets each criterion and name trade-offs, instead of stating only a total. Watch for evaluations where designs got different tests, or where rules were changed after the results came in.
02
Classroom Activities
3 Activities
1
Foil Boat Showdown: Build, Test, Score
35 minGroups of 3
The class compares four hull designs for a foil boat that must carry as many pennies as possible. Before building, the class writes the constraints and the scoring scales. Each group builds and tests one design three times, and the class pools the results into one decision matrix.
Procedure
Constraints, agreed first: one 20 × 20 cm square of foil per boat, no tape, and no more than 10 minutes to build. Criteria and scales, also agreed first: pennies held before sinking (3 points for 60 or more, 2 points for 45-59, 1 point for 30-44, 0 points below 30) and steadiness (3 points if it stays upright when 10 pennies are placed all on one side, 0 points if it tips).
The four designs: a flat raft with 1 cm folded edges, a deep box with 4 cm walls, a pointed canoe, and a box with double-thick folded walls.
Float each boat in a tub of tap water. Add pennies one at a time, gently, at the center, until water comes in. Record the last count before sinking. Test three boats of the same design and use the mean.
Safety: fold over any sharp foil edges, wipe up spills right away, and wash hands after handling the pennies.
Sample Data (invented)
Mean pennies held: flat raft 38, deep box 61, canoe 27, double-wall box 55. Steadiness: the flat raft and the deep box stayed upright; the canoe and the double-wall box tipped. The double-wall box needed 2 foil squares to make.
Discussion Questions
Which design must be screened out before any scoring, and why does its high penny count not matter?
Score the other three designs and find their totals. Which design best meets the criteria, and what is its trade-off, if any?
Why did the class agree on the scales before anyone built a boat?
Modification for Distance Learning
Students build one design at home with kitchen foil and coins, post their counts to a shared table, and complete the class matrix together on a slide.
2
Reference Design Comparison: Tablet Stands
20 minPairs
Pairs use a Pugh chart to compare four cardboard tablet stand designs (W, X, Y and Z, shown on printed cards) with a reference design R: a plain triangle of folded cardboard. For each criterion, they mark + if the design is better than R, 0 if it is about the same, and - if it is worse.
Add the pluses and minuses for each design. Which designs beat the reference, and which only match it?
Two designs tie for the highest total. What does a Pugh chart not tell you about them, and what test would settle the choice?
Design Z is worse than R on criterion 1. Should that rule it out? Explain using the problem's priorities.
Challenge Variation
Pairs build the two leading designs from a cereal box and test them with a real tablet or a book of the same size, then decide whether the Pugh chart predicted the better one.
3
Fair or Not? Evaluation Detective Stations
25 minGroups of 3-4
Four stations each describe how an invented team evaluated its competing designs. Groups decide whether each evaluation was systematic, name what went wrong, and rewrite the faulty step. Groups rotate every 6 minutes.
Station Cases
Station 1, paper towers: Tower 1 was tested indoors and Towers 2 and 3 outside on a windy afternoon. Tower 1 stood 52 cm tall without falling; Towers 2 and 3 fell at 40 and 45 cm.
Station 2, water filters: The team wrote its scoring scale after testing: "3 points for the clearest water," and gave it to its own favorite.
Station 3, phone chargers: Charger B scored the highest total, 11 of 12 points, but it gets hot enough to melt plastic, which breaks the safety constraint.
Station 4, lunchroom trays: Each tray was scored 0-3 on four criteria, using scales written before testing, and every tray was tested by the same student in the same way. Totals: 8, 10, 7.
Discussion Questions
Only one station describes a systematic evaluation. Which one, and what makes it fair?
At Station 1, does the data show that Tower 1 is the best design? What would you change?
At Station 3, should the team choose Charger B because its total is 11 out of 12? Explain.
Modification for Distance Learning
Post the four cases as slides. Groups vote in a poll on whether each evaluation is fair, then discuss and rewrite the faulty steps in breakout rooms.
03
Diagrams & Visual Aids
2 diagrams
Diagram 1: Five Steps of a Systematic Evaluation
The order of a systematic evaluation. Constraints screen designs out first, scales and weights are fixed before anyone sees the results, every design gets the same test, and the decision names the trade-offs. The box underneath traces the rabbit-proofing example from Direct Instruction.
Diagram 2: Seedling Survival for Four Designs, with the Scoring Bands (Invented Data)
Invented two-week trial with 50 lettuce seedlings per design, drawn to scale. The shaded bands are the survival scale the class set before the trial. The raised beds are drawn dashed because they were screened out on cost before scoring. The sprinkler's 70% sits exactly on the lower edge of the 1-point band.
04
Homework Assignment
~30 min
MS-ETS1-2 Homework: Evaluating Competing Designs
Directions: All test results and prices are invented for practice. Show every screen, score and total. End each problem with a sentence that says how well the best design meets the criteria and constraints.
Part 1: Screening and Scoring (Problems 1-2)
The cafeteria needs a rack for returned lunch trays. Constraints: it must fit a wall space 1.2 m wide and cost no more than $100. Rack 1: 1.0 m wide, $85, holds 40 trays. Rack 2: 1.5 m wide, $70, holds 60 trays. Rack 3: 1.1 m wide, $120, holds 55 trays. Rack 4: 1.2 m wide, $95, holds 48 trays. (a) Screen the racks and say which are left and why. (b) Score the capacity of the remaining racks on this scale: 3 points for 50 trays or more, 2 points for 40-49, 1 point below 40. (c) The racks tie on capacity. Use cost to break the tie, and explain whether that is a fair tie-breaker.
A class tested four kite designs in the same 15 km/h breeze. Time in the air: Kite 1, 12 s; Kite 2, 47 s; Kite 3, 30 s; Kite 4, 8 s. The scale, written before testing: 3 points for 45 s or more, 2 points for 30-44 s, 1 point for 15-29 s, 0 points below 15 s. (a) Score each kite. (b) Kites 1 and 4 both score 0. What information does the scale hide? (c) Explain why the scale had to be written before the test.
Part 2: Decision Matrices and Pugh Charts (Problems 3-4)
Three automatic pet feeder designs were scored 0-3. Feeder P: reliability 3, cost 1, easy cleaning 2, quiet 2. Feeder Q: reliability 2, cost 3, easy cleaning 2, quiet 3. Feeder R: reliability 3, cost 2, easy cleaning 3, quiet 1. (a) Find each total with equal weights. (b) The owner says a missed meal is the worst problem, so reliability counts 3 times as much. Find the weighted totals. (c) Did the leader change? Which result should the owner use, and why?
A team compares three water bottle carrier designs with a reference design on five criteria. Design 1: +, 0, -, +, +. Design 2: -, -, +, 0, +. Design 3: +, +, 0, -, 0. (a) Find each design's total. (b) Which designs beat the reference? (c) Design 3 is worse than the reference on criterion 4, which is "does not leak". Explain why the team might still need more information before choosing.
Part 3: Evaluating an Evaluation (Problems 5-6)
A team compared three bridge designs made of craft sticks. They tested Bridge A with a 2 kg load, and Bridges B and C with a 1 kg load. All three held. They chose Bridge C "because it looked the strongest," and they did not check the constraint that each bridge may use at most 50 sticks (Bridge C used 64). (a) List three steps that were not systematic. (b) Rewrite the evaluation plan so it is systematic.
Three door stop designs must hold a classroom door open against the breeze from a box fan. Constraints: cost no more than $10, and no part on the floor taller than 3 cm (a tripping hazard). Wedge A: holds the door, leaves no marks, $4, 2.5 cm tall. Wall magnet B: holds the door, leaves no marks on the floor but needs 2 screw holes in the wall, $12. Sandbag C: holds the door, leaves no marks, $3, 8 cm tall. (a) Screen the designs. (b) Recommend a design and explain how well it meets the criteria and constraints. (c) Name one trade-off or risk of your choice that the team should test next.
Rubric
Criterion
Full Credit (2 pts)
Partial Credit (1 pt)
Screening
Every design that breaks a constraint is removed before scoring, with the reason stated
One design screened incorrectly or no reason given
Scores and Totals
Scales applied exactly, including boundary values, and totals or weighted totals correct
One scoring or arithmetic error
Evaluation and Trade-offs
Explains how well the best design meets the criteria and constraints, names a trade-off, and identifies any unfair step
Names a winner without explaining trade-offs, or misses an unfair step
05
Quiz: 20 Questions
Interactive, with answers
Instructions
All test results, prices and scores are invented. Your score updates as you answer, and Reset quiz clears everything so you or your students can try again. Short-answer questions show a model answer.
Multiple choice: pick an option to check it. Short answer: write your answer, then reveal the model answer.
0 of 20 answered · 0 correct
Question 1 of 20 · Multiple Choice
What makes an evaluation of competing designs systematic?
Answer: C
A systematic process uses the same steps, criteria, scales and tests for every design, decided in advance. Choice A uses opinions with no shared rules, choice B assumes cost shows quality, and choice D lets builders judge their own work.
Question 2 of 20 · Multiple Choice
A team may spend at most $40 on a bird bath. The designs cost $35, $48, $22 and $41. How many designs pass the screen?
Answer: B
Only $35 and $22 are at or under $40, so 2 designs pass. Choice C keeps the $41 design, which is over budget by $1. Choice D forgets to screen at all, and choice A keeps only the cheapest one.
Question 3 of 20 · Multiple Choice
A scale for a water fountain design's fill time is: 3 points for 10 s or less, 2 points for 11-20 s, 1 point for 21-30 s, 0 points for more than 30 s. A design fills a bottle in 18 s. What score does it get?
Answer: D
18 s is in the 11-20 s band, so the design gets 2 points. Choice A would need 10 s or less. Choice B is the score for 21-30 s, and choice C is for more than 30 s.
Question 4 of 20 · Multiple Choice
Four glider designs were scored 0-3 with equal weights. Glider A: distance 3, durability 2, build time 1. Glider B: distance 2, durability 3, build time 2. Glider C: distance 3, durability 1, build time 2. Glider D: distance 1, durability 2, build time 3. Which glider has the highest total?
Answer: A
The totals are A 6, B 7, C 6 and D 6, so Glider B leads by 1 point. Choices B and C pick the gliders with the best distance score, which is only one of the three criteria. Choice D picks the fastest to build.
Question 5 of 20 · Multiple Choice
Criteria are weighted 3, 2 and 1. A design scores 2, 3 and 1 on them. What is its weighted total?
Answer: B
Multiply each score by its weight and add: 3 × 2 + 2 × 3 + 1 × 1 = 6 + 6 + 1 = 13. Choice A ignores the weights. Choice C pairs the weights in reverse order (1 × 2 + 2 × 3 + 3 × 1). Choice D multiplies the unweighted total 6 by the largest weight.
Question 6 of 20 · Multiple Choice
Why should a team write its scoring scales before it tests the designs?
Answer: D
If the scale is written after the results are known, a team can choose cut-offs that favor the design it already likes. Choice B is wrong because a fair scale still gives different totals to designs that perform differently. Choices A and C are not reasons for a systematic process.
Question 7 of 20 · Multiple Choice
In a Pugh chart, a design is marked +, +, 0, - and + compared with the reference. What is its total?
Answer: C
Three pluses and one minus give +3 - 1 = +2; the 0 adds nothing. Choice A ignores the minus. Choice B counts the 0 as a plus and ignores the minus, and choice D counts every mark as a plus.
Question 8 of 20 · Multiple Choice
Two designs tie for the highest total in a decision matrix. Which next step keeps the evaluation systematic?
Answer: C
Looking more closely at the top-priority criterion, or running a further test agreed in advance, uses the problem's own priorities. Choice D changes the rules after seeing the results, which is not systematic. Choices A and B ignore the criteria.
Question 9 of 20 · Multiple Choice
A team tested three umbrella stand designs. Stand 1 was tested with 4 umbrellas, and Stands 2 and 3 were each tested with 8. Stand 1 was the only one that did not tip over. What is the main problem with this evaluation?
Answer: A
Stand 1 carried a lighter load, so its result cannot be compared with the others. A fair comparison gives every design the same test. Choices B, C and D do not explain why the result is unfair.
Question 10 of 20 · Multiple Choice
A drinking fountain design scores the highest total of four designs, but it breaks the constraint that it must be reachable from a wheelchair. What should the team do?
Answer: B
Constraints are limits every solution must respect, so a design that breaks one is screened out no matter its score. Choices A, C and D all let a design that excludes wheelchair users stay in the running.
Question 11 of 20 · Multiple Choice
A team is choosing a design for a school-bus stop shelter. Which reason best justifies giving "keeps riders dry" a weight of 3 while other criteria get 1?
Answer: A
A weight should come from the problem: if keeping riders dry is the main purpose, it should count most. Choice B picks the weight to help a favorite, which bends the evaluation. Choices C and D are not reasons connected to the problem.
Question 12 of 20 · Multiple Choice
Two designs tie on total score. Design X scores 3 on safety and 1 on cost. Design Y scores 1 on safety and 3 on cost. The problem statement says safety is the top priority. Which choice is best supported?
Answer: C
When totals tie, the problem's priorities settle the choice, and here safety comes first, so Design X is better supported. Choice B ignores the stated priority. Choice A picks the criterion that matters less.
Question 13 of 20 · Multiple Choice
A matrix shows a rain gauge design that scores 3 for accuracy and 3 for cost, but 0 for durability. Which statement best describes how well it meets the criteria?
Answer: D
The scores show strengths in accuracy and cost and a weakness in durability, a trade-off to report. Choice A hides the weak criterion behind the total. Choice B judges by one score only, and choice C is false, since every design was scored the same way.
Question 14 of 20 · Multiple Choice
A team wants to choose among five shoe-rack designs. Which order of steps is systematic?
Answer: B
The constraints screen first, the scales are set before testing, every remaining design is tested the same way, and only then are scores given. Choices A and C decide the rules after results or without tests, and choice D tests designs unequally.
Question 15 of 20 · Short Answer
Three snack container designs were scored 0-3. Container 1: keeps snacks fresh 3, easy to open 1, cost 2. Container 2: fresh 2, open 3, cost 2. Container 3: fresh 2, open 2, cost 3. Freshness is the main purpose, so it counts 2 times as much. Find the weighted totals and recommend a container.
Weighted totals: Container 1 = 2 × 3 + 1 + 2 = 9; Container 2 = 2 × 2 + 3 + 2 = 9; Container 3 = 2 × 2 + 2 + 3 = 9. All three tie. Because freshness is the top priority, Container 1 is best supported, since it scores highest on freshness; its trade-off is that it is the hardest to open. (A further test of how easy it is to open would also be a reasonable next step.)
Question 16 of 20 · Short Answer
A team compares two new lunchbox designs with a reference design. Design M is better on insulation and cost, the same on size, and worse on weight. Design N is better on size, the same on insulation and cost, and worse on weight. Make the Pugh chart totals and say what they show.
Design M: +, +, 0, - gives +1. Design N: 0, 0, +, - gives 0. Design M beats the reference and Design N only matches it. Both are heavier than the reference, so weight is a shared weakness, and the chart does not show how much better or worse; the test numbers are needed for a close decision.
Question 17 of 20 · Short Answer
A team launched three fin designs on a water-bottle rocket once each, on the same day with the same launcher. Fins A flew 31 m, Fins B 29 m and Fins C 30 m. The team declared Fins A the winner. Explain why this evaluation is weak, and how to make it systematic.
One launch per design is not enough: the three distances differ by only 1-2 m, which is less than the change you would expect from one launch to the next of the same rocket (wind, how much water, how tightly it is pumped). A systematic plan sets the scale in advance, launches each design several times (for example, 3 launches) with the same amount of water and pressure, and compares the means. If the means are still within a meter or two, the team should call it a tie on distance and decide on its other criteria.
Question 18 of 20 · Short Answer
In the rabbit-proofing example, the budget was $150. Suppose the garden club raises the budget to $300. Explain how the evaluation would change, and what the class would need to do before choosing.
The raised beds ($260) would now pass the screen, so they join the matrix. The class would need to score them on every criterion with the same scales used for the other designs (their 80% survival already scores 2 points) and recalculate the totals before choosing. The other designs' scores stay the same, but the winner could change.
Question 19 of 20 · Short Answer
A team needs a scoring scale for the criterion "a backpack dries quickly after rain." Write a 0-3 scale that could be set before testing, and describe the test.
Sample scale: 3 points if the backpack is dry to the touch in 2 hours or less, 2 points for more than 2 and up to 4 hours, 1 point for more than 4 and up to 8 hours, 0 points for more than 8 hours. Test: spray every backpack with the same amount of water (for example, 500 mL) and hang them all in the same room, checking every 30 minutes.
Question 20 of 20 · Short Answer
A team evaluating three classroom bench designs finds: Bench A is the strongest but the heaviest to move; Bench B is the lightest but costs the most; Bench C is in the middle on everything and has the highest weighted total. Write a recommendation that explains how well the chosen design meets the criteria and names a trade-off.
Sample: "We recommend Bench C. It has the highest weighted total and meets every criterion and constraint, though it is not the best on any single one. Its trade-off is that it is weaker than Bench A and heavier than Bench B; if strength became the top priority, Bench A would be the better choice."
0 of 20 answered · 0 correct
06
Frequently Asked Questions
10 Questions
What does MS-ETS1-2 mean?
MS-ETS1-2 asks students to evaluate competing design solutions with a systematic process, to find how well each one meets the criteria and constraints of the problem. The key words are "systematic process": every design is judged by the same rules, decided in advance. The code means Middle School, Engineering, Technology and Applications of Science, core idea 1 (Engineering Design), performance expectation 2.
What grade is MS-ETS1-2 taught in?
It is a grades 6-8 standard, and schools usually teach it inside a science unit with a design project, after students have defined the criteria and constraints (MS-ETS1-1). Many teachers return to it each year with a new project.
What is a systematic process for evaluating designs?
It is a set of steps applied the same way to every design: screen out designs that break a constraint, set scoring scales and weights before testing, test every design the same way, score and total the results, and explain the decision. Decision matrices and Pugh charts are two common tools for doing this.
What is a decision matrix?
A decision matrix is a table with the designs in the rows, the criteria in the columns and a score in each cell. Adding across a row gives each design's total. Weights can make the most important criteria count more, as long as they are chosen from the problem's priorities before the totals are compared.
What is a Pugh chart?
A Pugh chart compares each design with one reference design, criterion by criterion, marking + for better, 0 for the same and - for worse. Adding the marks shows which designs beat the reference. It is quick and useful early on, but it shows only direction, not how much better or worse.
Does MS-ETS1-2 have an assessment boundary?
No. NGSS gives no Clarification Statement and no Assessment Boundary for MS-ETS1-2, so lessons follow the performance expectation itself. Students may use any systematic process, as long as it shows how well each design meets the criteria and constraints.
What is the difference between screening and scoring?
Screening removes designs that break a constraint, and scoring compares how well the remaining designs meet the criteria. A design that fails a constraint, such as a budget or a safety rule, is out before any points are given.
What mistakes do students often make when evaluating designs?
Many students pick a favorite first and then make the scores fit, change the rules after seeing results, or give different designs different tests. Others report only a total and skip the trade-offs. A checklist with "Was this decided before testing?" and "Did every design get the same test?" catches most of these.
How is MS-ETS1-2 different from MS-ETS1-3?
MS-ETS1-2 evaluates competing designs to see how well each meets the criteria and constraints. MS-ETS1-3 goes further: students analyze test data to find the best characteristics of each design and combine them into a new, better solution.
How does MS-ETS1-2 connect to other standards?
It builds on 3-5-ETS1-2, where students compare possible solutions, and on MS-ETS1-1, which defines the criteria and constraints used here. In high school, HS-ETS1-3 asks students to evaluate solutions to complex real-world problems using prioritized criteria and trade-offs. Ecology lessons also apply it in MS-LS2-5, which evaluates competing designs for protecting biodiversity.
07
Related Standards
5 standards
These standards connect to MS-ETS1-2: prerequisites to review first, parallel standards at the same level, and next steps that build on it.
Before this lesson
3-5-ETS1-2Prerequisite
Generate and compare solutions by how well each meets the criteria and constraints
Lesson coming soon
MS-ETS1-1Prerequisite
Define precise criteria and constraints for a design problem
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