Mirror Lake Elementary School
Federal Way, WA · Grades ?–5
Seattle-Tacoma-Bellevue, WA
NeighborhoodDecoded Rank
All factors combined
Bottom 30% decoded
#497 of 680
Seattle-Tacoma-Bellevue, WA schools
Below Expected
#1107 in WA
Achievement Rank
Raw test performance
Bottom 15% achievement
#631 of 680
Seattle-Tacoma-Bellevue, WA schools
#1364 in WA
Lower by Both Measures
This school ranks low on both raw achievement and decoded performance.
Data confidence:High468 students tested 8 years99% participation
Confidence is computed from sample size, year coverage, and participation rate. Higher confidence means the rank shift is stable across years and not driven by a single small cohort.
- Tested students: total students with valid scores across all reported years.
- Years of data: number of school years included. More years smooths year-to-year noise.
- Participation: share of enrolled students who took the assessment. Low participation can bias scores.
What's driving this rank
Decoded Rank: #497 of 680
in Seattle-Tacoma-Bellevue, WA schools
Raw test scores rank this school #631, but after accounting for context, students here outperform what the data would predict. The Decoded Rank places it at #497.
Each component below is scored on a 0–100 within-metro scale. A qualitative band summarizes where the school lands.
- About averagePerforms above what its context predictsCounts for 35% of the rank
After accounting for income and demographics, does this school beat what the data would predict?
- LowStudents gain ground year over yearCounts for 30% of the rank
Are kids at this school learning faster than typical for the metro?
- Above averageEquity within the schoolCounts for 15% of the rank
Are students clustered at similar levels, or split between top and bottom?
- About averageDirection over recent yearsCounts for 10% of the rank
Is this school's Decoded Rank trending up or down across the years we have data for?
- StrongMost students were testedCounts for 10% of the rank
Was the rank computed against a representative share of the school's students?
Show the numbersFor the methodology-curious
Each component is converted to a 0–100 within-metro percentile (100 = top of the metro). "Contribution" is the percentile-points the component adds to (or subtracts from) the metro median before the schools are re-ranked into the composite.
| Component | Weight | Percentile | Contribution |
|---|---|---|---|
| Performs above what its context predicts | 35% | 51 | +0.4 |
| Students gain ground year over year | 30% | 1 | -14.6 |
| Equity within the school | 15% | 71 | +3.2 |
| Direction over recent years | 10% | 50 | +0.0 |
| Most students were tested | 10% | 99 | +4.9 |
Why trust this?- Public data sources
- Context-adjusted model
- Confidence shown
- Methodology published
This score uses state assessment data, NCES enrollment data, and Census ACS 5-year neighborhood data. The Decoded Rank adjusts for school context — student demographics, ELL/SPED service rates, and the socioeconomic profile of the surrounding tract — and shows how the school performs relative to expectation, not in absolute terms.
SchoolDecoder is one signal, not a verdict. Decoded Rank is a context-adjusted residual, not a causal claim about teaching quality. See full methodology →
All Rankings
How this school ranks across the metro, state, and among demographic peers.
| Scope | Achievement | Decoded | Shift |
|---|---|---|---|
| Seattle-Tacoma-Bellevue, WA (680 schools) | #631 | #497 | |
| WA (1506 schools) | #1364 | #1107 | |
| Among similar schools (6 peers) | #4 | #4 |
Resource context
School inputs, not ranking points
These fields describe the school and surrounding neighborhood. They help readers interpret the page, but this is not a dollar-by-dollar or ratio-by-ratio scorecard and the fields here are not components of the Decoded Rank.
- Enrollment
- 491
- Free/reduced-price lunch
- 82.3%
- Student-teacher ratio
- 15.8:1
- Locale
- Suburb, large
- School type
- Regular public school
- Enrollment model
- Neighborhood attendance area
- Neighborhood median income
- $61,378ACS tract proxy
- Neighborhood poverty
- 0.2%ACS tract proxy
- SES index
- 11.7
- Assessment data year
- 2025
- CCD year
- 2024
- ACS vintage
- 2020-2024
Within Federal Way School District: #18 of 31.Middle quintile in district. View district
Performance Spread
How students are distributed across the four state-assessment proficiency levels — L1: below standard, L2: approaching, L3: meets (proficient), L4: exceeds. This describes the shape of results at the school, not their height.
Students at this school are typically spread across proficiency levels.
- Level 1 — Below standard51%
- Level 2 — Approaching standard24%
- Level 3 — Meets standard (proficient)16%
- Level 4 — Exceeds standard9%
Performance Spread measures how evenly students are distributed across the L1..L4 proficiency ladder, treating the levels as an ordered scale (L1=1, L2=2, L3=3, L4=4) and weighting each by its student share. A school where most students cluster at one level has a TIGHT spread; a school split between the bottom and top has a WIDE or BIMODAL spread. Bimodal fires only when BOTH tails are non-trivial AND the middle is relatively hollow (pct_L1 ≥ 15, pct_L4 ≥ 25, pct_L2 + pct_L3 ≤ 60). It describes shape — NOT how high the school's scores are. Methodology
Nearby Schools
Sorted by distance. Both rank columns shown so you can compare quickly.
- Federal Way High School0.7 mi
- Lake Grove Elementary School0.7 mi
- Support School1.0 mi
- Federal Way Running Start Home School1.0 mi
- Gateway to College1.0 mi
| School | Achievement | Decoded | Shift | Story | Confidence |
|---|---|---|---|---|---|
| Federal Way High School | Rankings coming soon. | ||||
| Lake Grove Elementary School | #646 | #620 | Lower by Both Measures | High | |
| Support School | Rankings coming soon. | ||||
| Federal Way Running Start Home School | Rankings coming soon. | ||||
| Gateway to College | Rankings coming soon. | ||||
Similar Schools
Schools with comparable demographics, income, and size. Both rank columns shown for direct comparison.
| School | Achievement | Decoded | Shift | Story | Confidence |
|---|---|---|---|---|---|
| Mission View Elementary School | #23 | #10 | Typical Profile | High | |
| Lochburn Middle School | #678 | #562 | Lower by Both Measures | High | |
| Cascade View Elementary | #669 | #626 | Lower by Both Measures | High | |
| Pioneer Middle School | #27 | #8 | ★★Outperforming Expectations | High | |
| Robertson Elementary | #32 | #42 | Typical Profile | High |
Historical Ranks
Year-by-year decoded and achievement ranks. Pandemic-affected years are excluded — we don't interpolate scores across the gap.
| Year | Achievement | Decoded | Shift |
|---|---|---|---|
| 2025 | #631 | #497 | |
| 2024 | #651 | #661 | |
| 2023 | #610 | #600 |
Note: assessment transitions (where a state changes its test) are footnoted on the methodology page; trends are not computed across breakpoints.
Trajectory
Trending up
Based on 3 years (2023–2025).
Slope: +6.3 pct/yr (95% CI -116.9 to 129.6)
Low confidence
How this works: we fit a linear trend across the available years of Decoded percentile, then bucket the slope into a direction. Wide confidence intervals (uncertain trends) collapse to Holding steady. See the methodology page for thresholds.
Cohort Progression
Kids who started 3rd grade here in 2015 lost 31 proficiency points by 5th grade.
Based on 16 cohorts across math + ELA.
Learning rate: -15.0 proficiency points/yr (95% CI -21.3 to -8.7)
Medium confidence
| Cohort | 2015 | 2016 | 2017 | 2018 | 2019 | 2023 | 2024 | 2025 | Slope |
|---|---|---|---|---|---|---|---|---|---|
| ELA · started 5th in 2015 | G5 269 | — | |||||||
| ELA · started 4th in 2015 | G4 246 | G5 263 | +17.3 | ||||||
| ELA · started 3rd in 2015 | G3 249 | G4 236 | G5 218 | -15.5 | |||||
| ELA · started 3rd in 2016 | G3 269 | G4 240 | G5 243 | -13.0 | |||||
| ELA · started 3rd in 2017 | G3 266 | G4 236 | G5 227 | -19.1 | |||||
| ELA · started 3rd in 2018 | G3 248 | G4 234 | -13.7 | ||||||
| ELA · started 3rd in 2019 | G3 243 | — | |||||||
| ELA · started 5th in 2023 | G5 209 | — | |||||||
| ELA · started 4th in 2023 | G4 179 | G5 159 | -20.4 | ||||||
| ELA · started 3rd in 2023 | G3 197 | G4 169 | G5 182 | -7.5 | |||||
| ELA · started 3rd in 2024 | G3 183 | G4 165 | -18.3 | ||||||
| ELA · started 3rd in 2025 | G3 193 | — | |||||||
| Math · started 5th in 2015 | G5 271 | — | |||||||
| Math · started 4th in 2015 | G4 237 | G5 237 | +0.8 | ||||||
| Math · started 3rd in 2015 | G3 258 | G4 242 | G5 204 | -27.3 | |||||
| Math · started 3rd in 2016 | G3 288 | G4 229 | G5 208 | -39.8 | |||||
| Math · started 3rd in 2017 | G3 272 | G4 245 | G5 228 | -22.1 | |||||
| Math · started 3rd in 2018 | G3 253 | G4 233 | -19.6 | ||||||
| Math · started 3rd in 2019 | G3 266 | — | |||||||
| Math · started 5th in 2023 | G5 172 | — | |||||||
| Math · started 4th in 2023 | G4 163 | G5 137 | -26.7 | ||||||
| Math · started 3rd in 2023 | G3 185 | G4 197 | G5 181 | -1.6 | |||||
| Math · started 3rd in 2024 | G3 202 | G4 185 | -17.1 | ||||||
| Math · started 3rd in 2025 | G3 188 | — |
How this works: we follow each grade-cohort across years through the school (3rd graders in 2023 are 4th graders in 2024, etc.) and fit a linear slope on a 100–400 proficiency-points scale built from the state assessment's four levels (L1=1, L2=2, L3=3, L4=4, weighted by student share). This is the same construction Stanford SEDA uses (edopportunity.org/methods); it's not student-level tracking — we measure the school's cohort, not individuals. See the methodology page for thresholds.
Evidence & technical detailClick to expand
School Alpha
School Alpha is the residual between actual and expected performance once school context is held constant. It is a context-adjusted estimate, not a causal claim about teaching quality.
- Shrunk Alpha (95% CI)
- -0.00 (95% CI: -0.03 to +0.02)
SES index components
- SES method
- Blended SES index (ACS + FRL)
- SES index value
- 11.7
- FRL %
- 82.3%
- ELL %
- —
- SPED %
- —
- Tract median income (ACS 5-year)
- $61,378
- Tract poverty rate
- 0.2%
- Tract % bachelor's+
- 16.3%
What "Decoded Rank" means
Decoded Rank converts School Alpha — the context-adjusted residual — into a parent-facing rank within the metro pool. A higher Decoded Rank than Achievement Rank means the school's raw scores understate its performance once neighborhood and school context are held constant. The reverse means raw scores overstate it. The rank is one signal, not a verdict.