Grass Lake Elementary School
Kent, WA · Grades ?–5
Seattle-Tacoma-Bellevue, WA
NeighborhoodDecoded Rank
All factors combined
Bottom 15% decoded
#613 of 680
Seattle-Tacoma-Bellevue, WA schools
Lower Performance
#1332 in WA
Achievement Rank
Raw test performance
Middle 40% achievement
#219 of 680
Seattle-Tacoma-Bellevue, WA schools
#289 in WA
Typical Profile
This school performs roughly as expected for its context.
Data confidence:High430 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: #613 of 680
in Seattle-Tacoma-Bellevue, WA schools
Raw test scores rank this school #219, but families here have higher-than-average income and educational attainment, so the expected score is also high. After accounting for context, this school performs about as predicted — the Decoded Rank is #613.
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?
- LowEquity within the schoolCounts for 15% of the rank
Are students clustered at similar levels, or split between top and bottom?
- LowDirection 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% | 49 | -0.3 |
| Students gain ground year over year | 30% | 18 | -9.7 |
| Equity within the school | 15% | 5 | -6.8 |
| Direction over recent years | 10% | 0 | -5.0 |
| Most students were tested | 10% | 99 | +4.9 |
Note: this school's Alpha-only Decoded Rank is #347 (vs the composite #613). The composite includes cohort progression and other signals that diverge from the context-adjusted Alpha. See methodology.
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) | #219 | #613 | |
| WA (1506 schools) | #289 | #1332 | |
| Among similar schools (6 peers) | #5 | #5 |
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
- 337
- Free/reduced-price lunch
- 34.4%
- Student-teacher ratio
- 16.0:1
- Locale
- Suburb, large
- School type
- Regular public school
- Enrollment model
- Neighborhood attendance area
- Neighborhood median income
- $125,694ACS tract proxy
- Neighborhood poverty
- 0.0%ACS tract proxy
- SES index
- 81.4
- Assessment data year
- 2025
- CCD year
- 2024
- ACS vintage
- 2020-2024
Within Kent School District: #29 of 36.Bottom 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.
Two distinct groups are visible: a strong cluster at the top and a struggling cluster at the bottom.
- Level 1 — Below standard21%
- Level 2 — Approaching standard16%
- Level 3 — Meets standard (proficient)22%
- Level 4 — Exceeds standard40%
Why this matters. A bimodal distribution often reflects two student populations served side-by-side (for example a gifted or honors track alongside a general-population cohort). Aggregate scores can hide this. Look at the school's program mix when comparing.
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.
- Cedar Heights Middle School1.1 mi
- Jenkins Creek Elementary School1.1 mi
- Cedar Valley Elementary School1.4 mi
- Kentlake High School1.7 mi
- Crestwood Elementary School2.3 mi
| School | Achievement | Decoded | Shift | Story | Confidence |
|---|---|---|---|---|---|
| Cedar Heights Middle School | #533 | #664 | Lower by Both Measures | Medium | |
| Jenkins Creek Elementary School | #583 | #490 | Lower by Both Measures | High | |
| Cedar Valley Elementary School | #556 | #558 | Lower by Both Measures | High | |
| Kentlake High School | Rankings coming soon. | ||||
| Crestwood Elementary School | #323 | #609 | Typical Profile | High | |
Similar Schools
Schools with comparable demographics, income, and size. Both rank columns shown for direct comparison.
| School | Achievement | Decoded | Shift | Story | Confidence |
|---|---|---|---|---|---|
| Lowell Elementary School | #6 | #3 | ★Strong by Both Measures | High | |
| Littlerock Elementary School | #9 | #29 | High Scores, Context Matters | High | |
| Roosevelt Elementary School | #8 | #10 | ★Strong by Both Measures | High | |
| Bryant Center | Rankings coming soon. | ||||
| Aspire Middle School | #1 | #1 | ★Strong by Both Measures | 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 | #219 | #613 | |
| 2024 | #159 | #430 | |
| 2023 | #166 | #401 |
Note: assessment transitions (where a state changes its test) are footnoted on the methodology page; trends are not computed across breakpoints.
Trajectory
Trending down
Based on 3 years (2023–2025).
Slope: -9.2 pct/yr (95% CI -37.7 to 19.2)
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 gained 1 proficiency point by 6th grade.
Based on 18 cohorts across math + ELA.
Learning rate: -6.4 proficiency points/yr (95% CI -12.0 to -0.8)
Medium confidence
| Cohort | 2015 | 2016 | 2017 | 2018 | 2019 | 2023 | 2024 | 2025 | Slope |
|---|---|---|---|---|---|---|---|---|---|
| ELA · started 6th in 2015 | G6 342 | — | |||||||
| ELA · started 5th in 2015 | G5 312 | G6 318 | +6.2 | ||||||
| ELA · started 4th in 2015 | G4 312 | G5 331 | G6 326 | +6.9 | |||||
| ELA · started 3rd in 2015 | G3 312 | G4 323 | G5 334 | G6 313 | +1.3 | ||||
| ELA · started 3rd in 2016 | G3 338 | G4 309 | G5 305 | G6 307 | -9.6 | ||||
| ELA · started 3rd in 2017 | G3 319 | G4 311 | G5 312 | -3.4 | |||||
| ELA · started 3rd in 2018 | G3 309 | G4 305 | -3.4 | ||||||
| ELA · started 3rd in 2019 | G3 335 | — | |||||||
| ELA · started 6th in 2023 | G6 281 | — | |||||||
| ELA · started 5th in 2023 | G5 305 | — | |||||||
| ELA · started 4th in 2023 | G4 288 | G5 297 | +9.1 | ||||||
| ELA · started 3rd in 2023 | G3 300 | G4 291 | G5 268 | -15.9 | |||||
| ELA · started 3rd in 2024 | G3 306 | G4 284 | -21.5 | ||||||
| ELA · started 3rd in 2025 | G3 282 | — | |||||||
| Math · started 6th in 2015 | G6 365 | — | |||||||
| Math · started 5th in 2015 | G5 313 | G6 325 | +11.9 | ||||||
| Math · started 4th in 2015 | G4 322 | G5 349 | G6 342 | +10.0 | |||||
| Math · started 3rd in 2015 | G3 318 | G4 316 | G5 299 | G6 305 | -5.7 | ||||
| Math · started 3rd in 2016 | G3 345 | G4 303 | G5 310 | G6 305 | -11.4 | ||||
| Math · started 3rd in 2017 | G3 322 | G4 294 | G5 283 | -19.6 | |||||
| Math · started 3rd in 2018 | G3 316 | G4 312 | -4.0 | ||||||
| Math · started 3rd in 2019 | G3 331 | — | |||||||
| Math · started 6th in 2023 | G6 273 | — | |||||||
| Math · started 5th in 2023 | G5 284 | — | |||||||
| Math · started 4th in 2023 | G4 305 | G5 282 | -22.7 | ||||||
| Math · started 3rd in 2023 | G3 310 | G4 290 | G5 265 | -22.4 | |||||
| Math · started 3rd in 2024 | G3 306 | G4 284 | -21.3 | ||||||
| Math · started 3rd in 2025 | G3 299 | — |
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)
- -0.02 (95% CI: -0.05 to +0.01)
SES index components
- SES method
- Blended SES index (ACS + FRL)
- SES index value
- 81.4
- FRL %
- 34.4%
- ELL %
- —
- SPED %
- —
- Tract median income (ACS 5-year)
- $125,694
- Tract poverty rate
- 0.0%
- Tract % bachelor's+
- 37.2%
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.