Iteration 5 - Analysis: Statewide Testing

Iteration 5 - Analysis: Statewide Testing

Where is the most growth happening in statewide testing?

We have district data about 3rd and 8th grade achievement in reading, math, and writing. Consider that our data sources have absolute values, not growth. We’re interested in who is making the most progress, not who scores the highest. That means calculating growth by comparing the absolute values across two or more years.

A valid grade must be provided

Because there are multiple grades with which we could answer these questions, the grade must be provided, or an InsufficientInformationError should be raised.

ha.top_statewide_test_year_over_year_growth(subject: :math)
~> InsufficientInformationError: A grade must be provided to answer this question

And only valid grades are allowed.

ha.top_statewide_test_year_over_year_growth(grade: 3, subject: :math)
=> ...some sort of result...
ha.top_statewide_test_year_over_year_growth(grade: 8, subject: :math)
=> ...some sort of result...
ha.top_statewide_test_year_over_year_growth(grade: 9, subject: :math)
~> UnknownDataError: 9 is not a known grade

Finding a single leader

ha.top_statewide_test_year_over_year_growth(grade: 3, subject: :math)
=> ['the top district name', 0.123]

Where 0.123 is their average percentage growth across years. If there are three years of proficiency data (year1, year2, year3), that’s ((proficiency at year3) - (proficiency at year1)) / (year3 - year1).

Finding multiple leaders

Let’s say we want to be able to find several top districts using the same calculations:

ha.top_statewide_test_year_over_year_growth(grade: 3, top: 3, subject: :math)
=> [['top district name', growth_1], ['second district name', growth_2], ['third district name', growth_3]]

Where growth_1 through growth_3 represents their average growth across years.

Across all subjects

What about growth across all three subject areas?

ha.top_statewide_test_year_over_year_growth(grade: 3)
=> ['the top district name', 0.111]

Where 0.111 is the district’s average percentage growth across years across subject areas.

But that considers all three subjects in equal proportion. No Child Left Behind guidelines generally emphasize reading and math, so let’s add the ability to weight subject areas:

ha.top_statewide_test_year_over_year_growth(grade: 8, :weighting => {:math => 0.5, :reading => 0.5, :writing => 0.0})
=> ['the top district name', 0.111]

The weights must add up to 1.