Sanislo Elementary School
Seattle, WA · Grades K–5
Seattle-Tacoma-Bellevue, WA
NeighborhoodDecoded Rank
All factors combined
Middle 40% decoded
#472 of 678
plausibly #393–581
Seattle-Tacoma-Bellevue, WA schools
Performing as Expected
#1022 in WA
Achievement Rank
Raw test performance
Bottom 30% achievement
#553 of 678
Seattle-Tacoma-Bellevue, WA schools
#1156 in WA
Lower by Both Measures
Scores look modest, and the school performs below what its context predicts.
Data confidence:Medium166 students tested 7 years100% 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: #472 of 678
in Seattle-Tacoma-Bellevue, WA schools
Raw test scores rank this school #553, but after accounting for context, students here outperform what the data would predict. The Decoded Rank places it at #472.
Each component below is scored on a 0–100 within-metro scale. A qualitative band summarizes where the school lands.
- LowPerforms 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?
- Above averageStudents 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?
- 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% | 9 | -14.5 |
| Students gain ground year over year | 30% | 61 | +3.2 |
| Equity within the school | 15% | 76 | +3.9 |
| Direction over recent years | 10% | 0 | -5.0 |
| Most students were tested | 10% | 100 | +5.0 |
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 (678 schools) | #553 | #472 | |
| WA (1503 schools) | #1156 | #1022 | |
| 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
- 171
- Free/reduced-price lunch
- 74.3%
- Student-teacher ratio
- 12.2:1
- Locale
- City, large
- School type
- Regular public school
- Enrollment model
- Neighborhood attendance area
- Neighborhood median income
- $155,865ACS tract proxy
- Neighborhood poverty
- 0.1%ACS tract proxy
- SES index
- 65.1
- Assessment data year
- 2024
- CCD year
- 2023
- ACS vintage
- 2020-2024
Within Seattle School District No. 1: #62 of 78.Bottom-40% 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 cluster closely on the proficiency ladder.
- Level 1 — Below standard40%
- Level 2 — Approaching standard27%
- Level 3 — Meets standard (proficient)23%
- Level 4 — Exceeds standard10%
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.
- Career Link0.6 mi
- Louisa Boren STEM K-80.6 mi
- West Seattle Elementary School0.7 mi
- David T. Denny International Middle School0.7 mi
- Chief Sealth International High School0.8 mi
| School | Achievement | Decoded | Shift | Story | Confidence |
|---|---|---|---|---|---|
| Career Link | Rankings coming soon. | ||||
| Louisa Boren STEM K-8 | #403 | #643 | Typical Profile | Medium | |
| West Seattle Elementary School | #290 | #161 | ★★Outperforming Expectations | Medium | |
| David T. Denny International Middle School | #505 | #292 | Typical Profile | Medium | |
| Chief Sealth International High School | 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 |
|---|---|---|---|---|---|
| La Conner High School | Rankings coming soon. | ||||
| Fruit Valley Elementary School | #414 | #218 | Typical Profile | Medium | |
| Mesa Elem | #33 | #21 | Typical Profile | Medium | |
| Paul Rumburg Elementary | #25 | #31 | Lower by Both Measures | High | |
| Pasco Innovative Experiences and e-Learning | #50 | #34 | Typical Profile | Low | |
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 |
|---|---|---|---|
| 2024 | #553 | #472 | |
| 2023 | #539 | #622 |
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 2 years (2023–2024).
Slope: -10.1 pct/yr (no CI — too few years)
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 4th grade here in 2023 lost 21 proficiency points by 5th grade — declining, versus a metro median of about 0/yr.
Cohort-to-cohort variance is high — interpret the headline cautiously.
Learning rate: -2.9 proficiency points/yr (95% CI -11.0 to 5.3)
Medium confidence
| Cohort | 2015 | 2016 | 2017 | 2018 | 2019 | 2023 | 2024 | Slope |
|---|---|---|---|---|---|---|---|---|
| ELA · started 5th in 2015 | G5 197 | — | ||||||
| ELA · started 4th in 2015 | G4 192 | G5 234 | +42.0 | |||||
| ELA · started 3rd in 2015 | G3 198 | G4 230 | G5 209 | +5.4 | ||||
| ELA · started 3rd in 2016 | G3 206 | G4 193 | G5 190 | -7.8 | ||||
| ELA · started 3rd in 2017 | G3 169 | G4 189 | G5 185 | +8.1 | ||||
| ELA · started 3rd in 2018 | G3 217 | G4 224 | +7.2 | |||||
| ELA · started 3rd in 2019 | G3 176 | — | ||||||
| ELA · started 5th in 2023 | G5 257 | — | ||||||
| ELA · started 4th in 2023 | G4 203 | G5 241 | +38.0 | |||||
| ELA · started 3rd in 2023 | G3 194 | G4 213 | +19.4 | |||||
| ELA · started 3rd in 2024 | G3 178 | — | ||||||
| Math · started 5th in 2015 | G5 168 | — | ||||||
| Math · started 4th in 2015 | G4 231 | G5 200 | -30.8 | |||||
| Math · started 3rd in 2015 | G3 218 | G4 211 | G5 180 | -19.1 | ||||
| Math · started 3rd in 2016 | G3 211 | G4 218 | G5 179 | -16.0 | ||||
| Math · started 3rd in 2017 | G3 190 | G4 179 | -11.1 | |||||
| Math · started 3rd in 2018 | G3 247 | G4 219 | -28.3 | |||||
| Math · started 3rd in 2019 | G3 197 | — | ||||||
| Math · started 5th in 2023 | G5 214 | — | ||||||
| Math · started 4th in 2023 | G4 186 | G5 166 | -20.7 | |||||
| Math · started 3rd in 2023 | G3 216 | G4 223 | +6.5 | |||||
| Math · started 3rd in 2024 | G3 191 | — |
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.
Student Growth (Washington)
Student growth percentile: the typical student here grew faster than 53% of Washington students with similar score histories.
Median Student Growth Percentile (SGP), as published by Washington's Office of Superintendent of Public Instruction. 50 is exactly typical for the state. Based on 8 years of data.
| Year | Math SGP | ELA SGP | Students |
|---|---|---|---|
| 2015 | 56 | 61 | 136 |
| 2016 | 39 | 67 | 139 |
| 2017 | 40 | 41 | 154 |
| 2018 | 47 | 51 | 124 |
| 2019 | 57 | 51 | 117 |
| 2023 | 42 | 55 | 86 |
| 2024 | 54 | 65 | 113 |
| 2025 | 50 | 55 | 96 |
Washington did not administer statewide tests during 2020–2022, so those years are absent — a gap in the data, not a score of zero.
How this works: a Student Growth Percentile compares a student's score change to other Washington students who started at a similar place, so it measures growth independent of where a student began. We show Washington's published medians; Oregon does not publish student growth percentiles, so this panel never appears on Oregon schools. See the methodology page for how growth enters the Decoded Rank.
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)
- -0.62 (95% CI: -0.71 to -0.52)
SES index components
- SES method
- Blended SES index (ACS + FRL)
- SES index value
- 65.1
- FRL %
- 74.3%
- ELL %
- 34.5% · WA OSPI Report Card Enrollment
- SPED %
- 15.8% · WA OSPI Report Card Enrollment
- Tract median income (ACS 5-year)
- $155,865
- Tract poverty rate
- 0.1%
- Tract % bachelor's+
- 53.5%
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.