Aligning Assessment to Content Standards: Applying the Project
2061 Analysis Procedure to Assessment Items in School Mathematics
George E. DeBoer, AAAS Project 2061
Paul Ache, Kutztown University of Pennsylvania
American Educational Research Association Annual Meeting
Montreal, Canada April 12, 2005
This study was designed to determine the effectiveness of a procedure
to improve the alignment of mathematics assessment items to targeted
state content standards.
The study was conducted on over 100 released items from a single
state in the Northeast. The items were analyzed using a procedure
developed by Project 2061 of AAAS. There were three broad criteria
on which the items were analyzed:
- Content Alignment: Is the knowledge
specified in the content standard needed to answer correctly or can
the correct answer be obtained in some other way? Is the knowledge
specified in the content standard enough by itself to make a satisfactory
response or is additional knowledge or skill needed as well?
- Likely Effectiveness: (Referred
to as “item efficiency” in the poster.) Is there anything
in the item, which is not related to understanding the ideas in the
targeted content standard, that might interfere with a student’s
ability to respond correctly? Issues include comprehensibility, appropriateness
of the task context, and “guessability.” The objective
is to reduce the number of false negative and false positive answer
choices.
- Plausibility of Answer Choices: Are
all answer choices plausible and related to the ideas being tested?
For example, are distractors related to students’ misconceptions
and commonly held beliefs?
Teams of analysts produced written profiles
that described each item’s alignment with the targeted content
standard and provided suggestions for revision. Items were revised
on the basis of the analysis criteria. It is important to note that
the items were not revised on the basis of an examination of student
responses on the original items.
Revised and original items were given to students who were asked
to show their work, explain how they obtained their answer, and to
indicate if anything about the item was confusing. Two forms of a
test were created for each grade. Half of the items on each form were
original and half were revised. Test forms were distributed randomly
in each class. Data were analyzed to determine the impact that revisions
had on improving the match between students’ answer choices
and their written explanations. The study provided information about
the effectiveness of this analysis procedure for improving the alignment
of assessment items to content standards. Summary data presented here
are for six items that were field tested with 259 eleventh grade students.
A complete analysis of two items appears at the end of this paper.
Table 1: Comparing Results for Six Original
and Revised Items
|
Provided
Explanations (%) |
False
Neg/Pos
(%) |
Confused
by
Wording (%) |
Confused
Total (%) |
Difficulty
(% correct) |
Item |
Orig. |
Rev. |
Orig. |
Rev. |
Orig. |
Rev. |
Orig. |
Rev. |
Orig. |
Rev. |
1 |
81.5 |
77.1 |
18.6 |
1.9 |
9.3 |
0.9 |
9.3 |
12.0 |
88.2 |
85.0 |
2 |
70.0 |
73.9 |
17.3 |
21.6 |
14.3 |
8.0 |
22.4 |
19.3 |
52.1 |
60.5 |
3 |
74.8 |
80.6 |
13.5 |
0.0 |
0.0 |
0.0 |
39.3 |
17.0 |
26.9 |
41.0 |
4 |
71.2 |
64.7 |
3.0 |
9.1 |
13.1 |
29.9 |
25.2 |
59.7 |
57.6 |
28.6 |
5 |
72.7 |
85.0 |
10.2 |
8.8 |
2.3 |
2.7 |
22.7 |
27.4 |
48.8 |
48.8 |
6 |
73.4 |
73.8 |
7.8 |
2.2 |
3.9 |
5.5 |
12.7 |
17.8 |
66.9 |
58.2 |
Mean |
73.9 |
75.9 |
11.7 |
7.3 |
7.2 |
7.8 |
21.9 |
25.5 |
56.8 |
53.7 |
Conclusions
- Whenever possible, the procedure should make use of student response
data before items are revised. The purpose of the analysis procedure
is to reduce the number of student responses that do not accurately
reflect what they know and can do. Some of the factors that lead
students to answer correctly when they do not have the required knowledge
and incorrectly when they do, are not apparent until student responses
are examined.
- When students are asked to provide explanations for their answers
or to show their work, approximately 75% of them do so. The comments
that they make are helpful for determining if the answer they selected
on a multiple choice test is consistent with their understanding
as shown in their work and explanations.
- When students are asked if anything in an assessment task is confusing
to them, they answer in three ways: (1) they identify specific mathematics
content that they do not understand; (2) they identify specific wording
or aspects of the structure of the item that is confusing; and (3)
they offer comments about being confused in general, without specifying
what was confusing to them. Most answers to this question are about
content confusion, although in a small but significant number of
cases the students provide specific information about wording that
is helpful when revising items.
Analysis of Item 1
Targeted Content Standard: Use operations (e.g.
opposite, reciprocal, absolute value, raising to a power, finding
roots, finding logarithms.)
Original Item 1
Which of the following represents the largest value?
- 103
- (5 + 5) X 10
- 108 / 102 (correct)
- 103 X 102
Analysts determined that the part of the content standard dealing
with “raising to a power” was necessary to respond
correctly to this task. Students had to use that operation to decide
which of a set of numbers that used exponents was larger. Analysts
also determined that the targeted standard was not sufficient (i.e.,
enough by itself) to respond correctly to this task because students
also needed to know how to “compare quantities and
magnitudes of numbers.” Although “comparing quantities” is
a fifth grade content standard, analysts felt it was worth noting
that this skill was needed and that it could not be assumed that all
students would have mastered it. Analysts judged that the item was
prone to guessing because the correct response is both the largest
value and contains the largest exponent. It was felt that students
might choose the correct answer even if they did not understand the
ideas in the content standard because the correct answer contains
the largest exponent.
Student Responses to the Original Item
One-hundred-nineteen responses were returned
from the three schools participating in the pilot study. The table
below shows the number and percent of students who showed their work
or provided an explanation for their answer and the distribution
of responses for the item.
Table 2: Student Responses to Original Item
1
|
A |
B |
*C |
D |
No
Response |
Total |
Explanation |
1 |
0 |
86 |
8 |
2 |
97 |
No
Explanation |
0 |
0 |
19 |
3 |
0 |
22 |
Total |
1 |
0 |
105 |
11 |
2 |
119 |
Percent |
.8 |
0.0 |
88.2 |
9.2 |
1.7 |
100.0 |
Analyzing the Responses of Students who Provided an Explanation
for their Work: Determining False Negatives and False Positives for
Original Item 1
Of the 97 students who showed their work or provided an explanation
for their answer, 86 students responded correctly to this task and
11 responded incorrectly.
Students Who Chose Answer A. One student chose A. This
student calculated the value of each answer choice correctly, showing
that 1,000,000 was the largest value, but circled the wrong answer.
This is a false negative, but not attributable to the structure of
the item.
Students Who Chose Answer B. No student chose response
B.
Students Who Chose Answer C (correct). Of the 86 students
who responded correctly, seven showed significant errors in their
work. Five of them made errors in how they evaluated the expression
in C (the correct answer) and two of them made errors in how they
evaluated expressions in the distractors. One student who chose the
correct answer simplified 108 as 40, 102 as 20, and indicated that
the quotient of those was 60. One student simplified 10/10 as 1, and
then wrote “8-2=7.” Two students simplified the expression
in C incorrectly but chose it as the correct answer because it was
the largest value. The remaining student chose C because “it
have to be the largest value…” The responses of the seven
students who answered correctly but whose work showed that they did
not understand the targeted content standard were judged to be false
positives. However, the student work and explanations did not provide
any evidence that they got the answer correct because of the way the
item is structured. We were unable to discern if guessing played a
role, i.e., if any of the students chose the correct answer C because
it had the largest exponent.
Students Who Chose Answer D. The eight students who chose
D evaluated the expressions in choices A, B, and C correctly, but
they evaluated the expression in D incorrectly. Most of these students
interpreted the expression 103 x (10)2 as (103 x 10)2, which would
make it the largest value. These eight students indicated that the
form of the expression in response D confused them. Because 103 x
(10)2 is a non-standard form to many students, and because these eight
students were able to correctly evaluate all of the other statements,
we judged these eight wrong answers to be false negatives. This is
something that could be changed in a future revision.
Students Who Chose no Answer. The two students who did
not choose any answer evaluated all expressions correctly but did
not circle an answer choice. These two responses were judged to be
false negatives but not attributable to the structure of the item.
Summary of False Negatives and False Positives for Original
Item 1. There were eighteen student responses that did not
accurately indicate what the students did or did not know with respect
to the targeted content standard (eleven false negatives and seven
false positives). We attributed eight of the eleven false negatives
to students being presented with a non-standard form of representing
exponents in one of the answer choices. Because this represents additional
knowledge to what is specified in the learning goal, this could also
qualify as a sufficiency issue, although not one that was identified
by the original analysts. It is certainly something that could be
addressed in future revisions. Three of the eleven false negatives
were due to students either circling the incorrect answer or circling
no answer even though they had shown how to calculate the correct
answer.
The seven false positives may have been due to student guessing
as predicted by the analysts. In each case, the students showed that
they did not know how to evaluate expressions containing exponents
but still chose the correct answer. Perhaps they chose the answer
that contained the largest exponent. However, no direct evidence was
found in the student work or comments to confirm this possibility.
In fact, only one student indicated that he or she chose correct answer
C because “it had the largest numbers,” and even that
does not speak directly to the size of the exponent.
Revised Item 1
Which of the following expressions represents the value 10,000?
- 104 - 100
- 102 + 102
- 108 / 102
- 104 X 100 (correct)
Results from Revised Item 1
One-hundred-forty responses were returned from the three
schools participating in the pilot study. The table below shows the
number and percent that showed their work or provided an explanation
for their answer and the distribution of responses for the item.
Table 3: Student Responses to Revised Item 1
|
A |
B |
C |
*D |
No
Response |
Total |
Explanation |
8 |
5 |
1 |
91 |
3 |
108 |
No
Explanation |
2 |
0 |
2 |
28 |
0 |
32 |
Total |
10 |
5 |
3 |
119 |
3 |
140 |
Percent |
7.1 |
3.6 |
2.1 |
85.0 |
2.1 |
100.0 |
Analyzing the Responses of Students who Provided an Explanation
for their Work: Determining False Negatives and False Positives for
Revised Item 1
Of the 108 students who showed their work or provided an explanation
for their answer, 91 students responded correctly to this task and
17 responded incorrectly.
Students Who Chose Answer A. Of the eight students who
chose A, six noted that 100 = 0, and two students correctly simplified
104 as 10,000 without indicating a value for 100, suggesting that
they also thought that 100 = 0.
Students Who Chose Answer B. Five students chose B, all
of whom simplified the expression 102+102 as (100)(100) = 10,000.
Students Who Chose Answer C. The only student choosing
C showed correct calculations for each expression, but chose the wrong
answer. This is a false negative but not attributable to the structure
of the item.
Students Who Chose Answer D (correct). Of the ninety-one
students who chose the correct answer D, a variety of reasons were
given for why they chose the answer. In no case was there enough evidence
to suggest they did not understand the ideas in the content standard
and, therefore, these responses were counted as valid responses.
Students Who Chose no Answer. Of the three students who
did not circle an answer, two simplified 100 as 10 and said that there
were no expressions equal to 10,000. The third student calculated
each response correctly, but did not circle an answer. This student’s
answer was counted as a false negative but not one that can be addressed
by changing the item.
Summary of False Negatives and False Positives for Revised
Item 1. Two student answer choices did not accurately represent
what they did or did not know with respect to the targeted content
standard (two false negatives and no false positives). These two
answer choices were either due to circling the wrong answer or circling
no answer even though the work was correct.
Comparing Original and Revised Item 1
Do the Revisions Increase the Validity of Student Selections? There
were fewer false negatives and false positives for the revised item
than for the original item. This can be attributed to the elimination
of the non-standard form of the exponent in the original item answer
choice D and, possibly, the removal of the largest exponent in the
correct answer choice C, which may have reduced guessing.
Table 4: False Negatives and False Positives
for Original and Revised Item 1
|
N |
False
Positives |
False
Negatives |
Total |
Percent
Invalid |
Original |
97 |
7 |
11 |
18 |
18.6 |
Revised |
108 |
0 |
2 |
2 |
1.9 |
Is the revised item less confusing to students? Results
of asking students if anything about the item is confusing are organized
into three categories: (1) content confusion, (2) confusion about
the way the item is worded or structured, and (3) non-specific confusion.
Table 5 summarizes the data for the students who found the item to
be confusing for the original and revised items.
Table 5: Comparing Degree of Confusion for Original
and Revised Item 1
|
Total
N |
Content
Confusion |
Confusion
About Item Structure or Wording |
Non-Specific
Confusion |
Percent
Confused |
Original |
97 |
0 |
9 |
0 |
9.3 |
Revised |
108 |
11 |
1 |
1 |
12.0 |
On the original item, nine students said something was confusing
to them. All nine students indicated that answer choice D confused
them because they did not know how to simplify the given expression
(wording or item structure), which is usually written as 102 not as
(10)2. On the revised item, thirteen students indicated that something
was confusing to them. Nine of them said that 100 was confusing (content),
one student did not understand the term “represent” (wording),
two students indicated not knowing how to cope with the superscript
(content), and one student claimed “the hole thing” to
be confusing (non-specific).
Item Difficulty. For all students who took the
test, both those who explained their answer and those who didn’t,
on the original item 88.2% of the students answered correctly and
on the revised item 85.0% of the students answered correctly. Changes
in the item had very little impact on item difficulty.
Analysis of Item 2
Targeted Content Standard: Apply ratio and
proportion to mathematical problem situations involving distance,
rate, and similar triangles.
Original Item 2
Kim needs a certain shade of pink paint for a handmade toy. This
shade is made by mixing white and red paint in a ratio of 1 to 3.
How many fluid ounces of red paint would be needed
to make 12 fluid ounces of this pink paint?
- 4 fluid ounces
- 6 fluid ounces
- 8 fluid ounces
- 9 fluid ounces (correct)
Analysts determined that the knowledge and skills specified in
the target content standard are both necessary and sufficient to
respond correctly to this task. Even though this item does not involve
the application of ratio and proportion to problems involving “distance,
rate, and similar triangles,” analysts felt that the contexts
specified in the content standard were meant to be illustrative and
that contexts like the one in this assessment task fell within the
scope of the content standard. Analysts did, however, note a lack
of clarity in the way the problem was originally written. In particular,
they felt that the first sentence does not contain much useful information,
the question is written in the passive voice, and when the question
is asked in the third sentence, it does not refer back to Kim.
Based on the comments of the analysts, it was decided that the item
would be revised solely on likely effectiveness issues. Therefore,
the item was revised to provide students with additional information
about the problem context in the first sentence. No attempt was made,
however, to change from passive to active voice or to refer back to
Kim in the second and third sentences. Although not done intentionally,
the task was also changed from one requiring the ability to deal with
part-to-whole comparisons to one requiring the ability to deal only
with part-to-part comparisons.
Student Responses to Original Item 2
One-hundred-forty responses were returned from
the three schools participating in the pilot study. The table below
shows the number and percent of students who showed their work or
provided an explanation for their answer and the distribution of
responses for the item.
Table 6: Student Responses to Original Item
2
|
A |
B |
C |
*D |
No
Response |
Total |
Explanation |
36 |
1 |
0 |
59 |
2 |
98 |
No
Explanation |
16 |
1 |
3 |
14 |
8 |
42 |
Total |
52 |
2 |
3 |
73 |
10 |
140 |
Percent |
37.1 |
1.4 |
2.1 |
52.1 |
7.1 |
100.0 |
Analyzing the Responses of Students who Provided an Explanation
for their Work: Determining False Negatives and False Positives for
Original Item 2
Of the 98 students who showed their work or provided an explanation
for their answer, 59 responded correctly and 39 responded incorrectly.
Students Who Chose Answer A. Of thirty-six students who
chose answer A, 22 divided 12 by 3 to get the answer 4. The remaining
14 students correctly used equivalent fractions but reversed the order
of red and white paint. These students demonstrated an understanding
of proportions as being two equivalent ratios, but they were confused
because the question stem does not specify whether one part is white
and three parts are red or if three parts are white and one part is
red. It merely says: “white paint and red paint in a ratio of
1 to 3.” It must be inferred that the order of the colors of
paint is the same as the order in which they are presented in the
problem. Some students explicitly mentioned this as being confusing,
but others may have mistakenly reversed the order without knowing
it. Based on the evidence that we have, we concluded that it is likely
that these students have an understanding of the target content standard
and got the question wrong because they were not sure of the labeling
that accompanied the given ratio. These fourteen responses were considered
to be false negatives that were due to an aspect of the task that
could be corrected in future revisions.
Students Who Chose Answer B. One student chose answer B.
This student began by correctly showing the equivalence of 1/3 and
2/6, but stopped at that point and chose 6 as the answer.
Students Who Chose Answer C. No students chose C.
Students Who Chose Answer D (correct response). Of the
59 students who chose D, 51 showed a clear understanding of the ideas
of ratio and proportion that are needed to solve the problem. They
showed that they understood that the expression 1:3 indicates the
relation between the parts (white and red paint), that they needed
to add 1 and 3 to get the whole (the pink paint); and that they had
to find the equivalent ratio 3:9 that added to 12. Students did this
in a number of ways, but in each case their understanding of the ideas
in the content standard was evident.
Eight students used strategies that suggested that they did not
understand the required ideas or they did not provide enough information
to tell if they understood the ideas in the content standard or not.
For example, five students claimed to use “logic,” or “did
it in my head.” Three students got the correct answer, but mentioned
not understanding ratios. One of these students subtracted 3 from
12 to get the correct answer D. The other two students added 9 and
3 and then circled the correct answer D. Based on what was said by
these students, it appears that even though they chose the correct
response, they did not understand the ideas in the targeted content
standard. The three students who found the answer, 9, as the difference
between 12 and 3 and said they did not understand ratios were classified
as false positives. The five who said they did it in their heads or
used logic did not give us enough information to classify them as
false positives.
Students Who Chose No Answer. Two students did not circle
any answer, and their work showed they did not understand the ideas
being tested.
Summary of False Negatives and False Positives for Original
Item 2. On the original item there were 14 false negatives
that are attributable to the imprecise wording of the task, specifically
the imprecision about the order of paints in the ratio. There were
three false positives that are attributable to the fact that the
numbers 12 and 3 appear in the stem and the number 9 appears in the
correct answer choice. Three students found the correct answer by
finding the difference between 12 and 3. This could be corrected
in a revision by using numbers in the stem that do not allow for
a solution by addition or subtraction. (For example, the question
could say that pink paint is made by mixing white and red paint in
the ratio of 1 to 4, and then ask how many ounces of red paint are
needed to make 15 ounces of pink paint. The numbers 15 and 4 would
appear in the stem, and the correct answer would be 12.)
Revised Item 2
Kim is painting a handmade toy and she needs to mix paint so she
can create a certain shade of pink. This shade is made by mixing
white paint and red paint in a ratio of 2 ounces to 5 ounces. How
many ounces of red paint are needed to mix with
100 ounces of white paint to create the right shade of pink?
- A. 500 ounces
- B. 250 ounces (correct)
- C. 40 ounces
- D. 20 ounces
Results from Revised Item 2
One hundred nineteen responses were returned
for the revised item from the three schools participating in the
pilot test. The table below shows the number and percent of students
who showed their work or provided an explanation for their answer
and the distribution of responses for the item.
Table 7: Student Responses to Revised Item 2
|
A |
B |
C |
*D |
No
Response |
Total |
Explanation |
2 |
60 |
19 |
1 |
6 |
88 |
No
Explanation |
3 |
12 |
8 |
4 |
4 |
31 |
Total |
5 |
72 |
27 |
5 |
10 |
119 |
Percent |
4.2 |
60.5 |
22.7 |
4.2 |
8.4 |
100.0 |
Analyzing the Responses of Students who Provided an Explanation
for their Work: Determining False Negatives and False Positives for
Revised Item 2
Of the 88 students who showed their work or provided an explanation
for their answer, 60 responded correctly and 28 responded incorrectly.
Students Who Chose Answer A. Two students chose answer
A. One of the students who chose A simply multiplied 100 by 5. The
other student multiplied 250 by 2. Both of these students demonstrated
that they did not understand the ideas in the content standard.
Students Who Chose Answer B (Correct). Sixty students chose
the correct answer B. Fifty-eight of them demonstrated appropriate
use of proportional reasoning to solve the problem. One additional
student demonstrated an understanding of proportions by arguing that
answer C (20 ounces of red paint) and answer D (40 ounces of red paint)
are not enough and if it was 500 ounces then there would be 200 ounces
of white paint. The remaining student wrote a series of ratios, beginning
with “4 to 10, 6 to 15, 8 to 20 …” and continued
to list ratios using this pattern. The final ratio was written as
92 to 250 instead of 100 to 250. This error did not provide sufficient
evidence that the student did not understand the targeted content
standard and, therefore, was not listed as a false positive. Even
if it were judged to be a false positive, it is not something that
could be affected by revising the item.
Students Who Chose Answer C. Nineteen students chose answer
choice C. Of these, 16 students showed they knew the correct way to
solve the proportion, but as in the original item they reversed the
order of the red and white paint, which led to an incorrect response.
The remaining three students who chose C provided an incorrect explanation
for their work. For the 16 responses where the order of red and white
paint was reversed, it was judged that these students understood the
ideas needed to answer correctly even though they got the wrong answer.
These 16 were considered to be false negatives.
Students Who Chose Answer D. One student chose answer choice
D. This student divided 100 by 5, indicating that the student did
not understand the ideas needed to answer correctly.
Students Who Chose No Answer or More than One Answer. Two
students circled two answers. One of these students was apparently
not sure of the order of the paint in the ratio because the student
listed the correct proportions for both answer B and C, solved them
both, and circled both responses. As with the students who chose C,
this response was counted as a false negative. The other student circled
answers A and C, wrote a series of fractions, and then claimed to
not know how to solve ratios. One student tried unsuccessfully to
write an equation. Two students provided correct work but did not
circle any of the response options. Although these were false negatives,
they were not due to anything that could be corrected in the structure
of the item.
Summary of False Negatives and False Positives for Revised
Item 2. On the revised item there were seventeen false negatives
that were attributable to the imprecise wording of the task, specifically
the imprecision in the order of paints in the ratio. There were also
two additional false negatives due to students not circling an answer.
There were no false positives on the revised item.
Comparing Original and Revised Item 2
Do the Revisions Increase the Validity of Conclusions about
what Students Know and do not Know? There were approximately
the same percentage of false negatives and false positives on the
original and revised items. These were due mostly to the imprecision
in how the order of the paints was stated in the questions. Although
this was not an issue that was addressed in the revision, it is clear
that if it had been, the number of invalid responses could have been
reduced significantly. The three false positives in the original
item were eliminated by changes that were made in the revised item.
Two of the false negatives on the revised items were due to students
not circling an answer even though they showed they understood the
ideas being tested.
Table 8: False Negatives and False Positives
for Original and Revised Item 2
|
N |
False
Positives |
False
Negatives |
Total |
Percent
Invalid |
Original |
98 |
3 |
14 |
17 |
17.3 |
Revised |
88 |
0 |
19 |
19 |
21.6 |
Is the revised item less confusing to students? Results
of asking students if anything about the item is confusing are organized
into three categories: (1) content confusion, (2) confusion about
the way the item is worded or structured, and (3) non-specific confusion.
Table 9 summarizes the data for the students who found the item to
be confusing for the original and revised items.
Table 9: Comparing Degree of Confusion for Original
and Revised Item 2
|
Total
N |
Content
Confusion |
Confusion
About Item Structure or Wording |
Non-Specific
Confusion |
Percent
Confused |
Original |
98 |
8 |
14 |
0 |
22.4 |
Revised |
88 |
0 |
7 |
10 |
19.3 |
Of the 22 students who claimed to be confused by some aspect of
the original item, eight students mentioned content issues, seven
of them claiming to not understand how to do ratio problems (content)
and one student not knowing how to divide the 12 into parts (content).
Fourteen students mentioned specific issues with the wording or structure
of the item, such as not knowing the order of paints in the ratio,
either red to white or white to red (wording). On the revised item,
responses from the 17 students who claimed to be confused fell into
two categories. Seven students claimed to be confused because they
did not know the order of the paints in the ratio (wording). The remaining
10 students claimed to not understand how to do the problem (non-specific)
but offered no reason.
Item Difficulty. For all students who took the
test, both those who explained their answer and those who did not,
52.1% of the students answered correctly on the original item and
60.5% of the students answered correctly on the revised item. The
greater number of correct responses on the revised item is most likely
due to the fact that the revised item requires fewer steps because
it eliminates the need to calculate the “whole” from the
two parts. The given ratio in both tasks compares part-to-part (red-to-white),
but in the original item students are required to take an additional
step: students needed to add the red part to the white part to get
the whole before answering this question. In the revised item, students
simply have to identify an equivalent part-to-part ratio.
The research reported here was supported by the National Science
Foundation (NSF Grant #9819018). Any opinions, findings, and conclusions
or recommendations expressed here are those of the authors and do
not necessarily reflect those of NSF.