Biotechnology for Health (Biomedical Innovations)

Unit 3: Problem 3: Designing a Medical InnovationBI 3.1Biomedical Innovation: validation & evidence

Build a decision matrix

Score design options against weighted criteria to choose the best one with evidence, not gut feeling.

Builds on (2 levels back)inferred · high confidence

Multiply then add (weighted totals): A weighted score multiplies each rating by its weight, then adds the products, so you must be able to multiply and sum.
Turn needs into criteria: A matrix's columns are the criteria; you first have to turn design goals into clear, comparable criteria.

Prerequisites are inferred: pending teacher review.

Re-learn the skill with worked practice and clear examples.

A decision matrix lists options as rows and criteria as weighted columns; you multiply each rating by its weight and add the products to get each option's weighted total.

Step 1: Build the table

Rows are your design options. Columns are the criteria. Each criterion gets a weight showing how much it matters.

Step 2: Score and weight

Rate every option on every criterion (for example 1 to 5). Multiply each rating by its column's weight to get a weighted value for that cell.

Step 3: Add across the row

Sum an option's weighted values across all criteria to get its weighted total. The highest total is the option the evidence favors.

Practice

Use the matrix shown. Criteria weights: Ease of Use = 3, Durability = 2, Cost = 1. What is the WEIGHTED TOTAL for Option A?

Approved

Option	Ease of Use (w=3)	Durability (w=2)	Cost (w=1)
A	4	5	2
B	5	3	4
C	3	4	5

A.11
B.24
C.22
D.26

Show the worked solution ▾

Answer: B. 24

Step 1: Weight each cell for Option A: Ease of Use: 4 times 3 equals 12. Durability: 5 times 2 equals 10. Cost: 2 times 1 equals 2.
Step 2: Add the products: 12 plus 10 plus 2 equals 24.

Why it's right: Option A: (4x3) + (5x2) + (2x1) = 12 + 10 + 2 = 24.

Why the others miss:

A: 11 just adds the ratings (4 + 5 + 2) and forgets the weights.
C: 22 is Option C's total, not Option A's.
D: 26 adds an extra 2, miscounting the Cost product.

Aligned to BI 3.1: computing a weighted total · reading level ~grade 9

Where you'd see this

A design team fills a weighted matrix for three prototypes so their final choice is backed by numbers in a report.

Careers that use this

Product Development Engineer: Uses a weighted decision matrix to defend which prototype moves forward to clients and managers.

Video library

Watch: Build a decision matrix

Decision Matrix: An Important Tool for Engineering Design

ITEEA · ~5 min

Guided notes

Fill these in as you work through the lesson.

Big idea: A decision matrix scores each design option against weighted criteria and adds up the weighted scores, so the choice is based on evidence instead of opinion.

Key terms: write the meaning

Decision matrix (a table of options scored against criteria):
Criterion (one thing you judge each option on):
Weight (how much a criterion matters):
Weighted score (rating times weight, then summed):

The rule

For each option, multiply every rating by its criterion's , then those products to get the option's weighted .

Check yourself

Why give some criteria a bigger weight than others?
What does a weighted score let you compare that a plain rating does not?
If two options tie on weighted total, what could you do next?

Work one example

A criterion 'Safety' has weight 3 and an option scores 4 on it. Find that one cell's weighted value, then explain how you would finish the option's total.