Technical Brief
A Visualization of the RI Model
A Visualization of the RI Model
While we can not draw a graph for multivariate analysis like one can do
with simple regression models; perhaps a virtual (spatial) image of the RI model would be
helpful. Imagine a large empty room with transparent walls. Inside the room is a set of
thousands of small balls suspended in space and stretching unevenly across the room. These
balls represent the actual scores of all students in one particular grade who took one of
the state tests. When you look into the room from the North (SES) side you notice that the
balls spread across the room are variously tinged with red ranging from brilliant red
(very poor) to very light, almost non-existent red (very wealthy). You note that most of
the brilliant red balls are concentrated in one end of the room and most of the very
light, almost non-existent red balls are concentrated in the far other end of the room.
However, you do note a few brilliant red balls scattered here and there throughout the
room, including even the far end where the very light balls hold sway.
Similarly, as you move to the West (Special Education) wall and peer into the room, you
now notice that the balls viewed from this angle are tinged with two types of blue The
deep blue balls represent students receiving services under special education law and the
light blue represents students not receiving any special education services. Once again
you note that most of the deep blue balls are near the same location in the room although
there are exceptions. Some light blue balls can be found throughout the room, but most are
concentrated toward one end of the room.
Now you move to the East (bilingual and LEP programs) wall and notice that there are two
kinds of purple balls - dark purple (receiving services) and light purple
(non-recipients). You note dispersal patterns among the purple balls similar to what you
have noted with the previous colors.
As you now move to a platform to peer down into the room from the top, you now see that
all the balls are colored from a bright yellow (very high achievement score) to clear (a
zero). However, you note a crucial difference from what you have seen in the room from the
other two walls. All of the bright yellow balls are in one end of the room and all of the
clear balls in the other. In fact, balls with identical or very similar shades of yellow
are uniformly found in the same approximate location within the room.
A person now opens the door into the room with a large transparent cube with colored balls
in it speckled with the blue and red hues you have already observed. Each ball is also
uniformly colored green (to represent the fact that these are all students from the same
school). He releases the balls into the room from the cube and they magically head to
various locations within the room. You note from your vantage point at the top of the room
that they all have arranged themselves at varying places within the room with some
concentrated at particular places and some existing solely by themselves with no other
green balls anywhere near them. As you descend to the West (special education) wall, you
see that nearly all the deep blue balls just released into the room have arrayed
themselves in the end of the room where most of the deep blue balls are concentrated.
Similarly, as you move to the North (SES) wall you notice that most of the brilliant red
balls from this school have arrayed themselves with their counterparts (other very poor
students from across the state) and the East (bilingual/LEP) wall similarly. Finally, as
you move to the South (school) wall, you notice clearly that you can easily pick out where
all the green balls are within the room. In fact you discover that you can count how many
are in each section of the room. The majority of balls representing student achievement
scores on this particular test from this particular school are concentrated within a given
area of the room. The person who released the balls now explains to you that what you have
seen is a statistical model of last year's student performance for the state. Each time
they release colored balls representing an individual school within the room, 95 times out
of a hundred, the balls end up in the approximate location where you now see them.
"Is it chance, or just coincidence?," he asks you. You reply, "I will have
to go to that school and see what I can find out."
Back to top
|| Return to the Information Works Home Page |
