Problems with True and False Tests

Teachers should know how to write and grade tests. Regrettably, they don't always use good assessment methods. 

True/False Tests and Guessing

Please answer the following true/false item:

___T ___F   Neils Bohr accepted the principal of complementarity as a necessary part of quantum theory.

If you actually participated in my one-question true/false "test" you had about a 50-50 chance of getting it right (unless you are quite knowledgeable regarding quantum theory). The question was easy for me to write-- I modified a phrase from a website. 

True/false tests have perhaps two advantages over other types of tests: (1) they are quickly written, and (2) they are quickly scored. 

These two advantages are both for the convenience of the teacher and do not offer students much. The trap for both students and teachers lies in the 50-50 chance of a correct or wrong answer. This encourages guessing-- not a test-taking skill to be encouraged. Also, because true/false items generally address simple concepts a large number of them is necessary to produce valid results. 

The chance factor is also important in scoring. Teachers typically grade them as they do other test items-- i.e., 20 items will count 5 points each (100% / 20 = 5). Thus a student who misses 10 of 20 will receive a score of 50. But if the items are fairly written a chimpanzee  trained to use a pencil could be expected to get half (10) of the items correct. Did the chimp know the answers? Likely not. Should the chimp receive 50 points based on chance? Well, if the teacher wants to grade according to knowledge the answer would be "No."

The correct way to grade true/false test and score for the "guess factor" is to multiply misses by two (the number of choices) and subtracting the result from the percent right. Each item counts 5 in a 20-question test. 

"Traditional" scoring simply deducts 5 points for each one missed:

100% - (5 X 10) = 50%

Scoring to compensate for guessing is different (and correct):

10 right X 5 = 50%;

10 wrong X 5 = 50%;
% right - % wrong + 50% - 50% = 0

Another view of the same "correction score" method is:

100% - two times the percent wrong;

100% - 2(50%) = 0

Students who score around 50% with traditional scoring techniques are demonstrating a score predicted by guessing! Of course, the same issue arises with any multiple choice test. After all, a true false test is a multiple choice test with 2 choices. The effect of guessing is reduced as more choices are added. 

Do True/False Tests have Value in Real Assessment?

The short answer is "Yes." But if a they must be used, consider them for formative (ungraded) activities designed for teaching simple concepts and adding variety to instructional methods. True/false worksheets can be an good exercise for homework.

True/false tests can be improved by having students justify their answers, but why not simply ask a short-answer question to begin with? 

By the way, the sample item at the beginning is "true."

Teaching Mistakes Teachers should Avoid

Teachers continue to make the same old teaching errors and ignore opportunities to improve. Student achievement suffers as a result.

Common instructional mistakes that teachers just won't give up.  

1. Incorrect use of homework. Homework is a formative activity -- i.e., it is assigned to help        teach new material. As such it should not be graded. If students see it as clearly related to learning they are more likely to do it. There should be no need to grade it; if homework is clearly relevant student grades will be lower on their tests. Why give zeros for missing homework if the student will receive a lower test grade because he did not use 

the learning opportunity homework offered. Tell parents about the missing homework.

2. Giving poor assessments. Teachers should understand formative and summative assessments and grade only summative. Also, teachers should not depend heavily on published assessments-- they might not agree with teacher vocabulary or syntax. 

3. Grades are for assessments, not behavior. Teachers should not deduct points for misbehavior or add points for behavior not related to learning. 

4. Avoid extra credit. If parents or students want extra credit allow them an opportunity to retake an alternate version of a failed assessment.

5. Screaming at students teaches them that you don't mean it unless you scream. 

6. Don't expect students to act like your children. Respect individuality.

7. Rewarding students with material "things" will not necessarily improve learning. There are problems with this practice. Dr. Marvin Marshall, an expert on motivation writes, "External controls are manipulators that set up students to be dependent upon external agents." 

8. Punishing the entire class. Would you want to pay a fine because your neighbor has a wild party? The practice turns peers against one another, while demonstrating that teachers have a right to be unjust.

We are Failing in Social Studies

American students and their parents are bombarded with information from television, the Internet, and other media. Not all of what is published or spoken is true. Politicians speak to the simple levels of our learning because we don't understand the complexities of government.

Rating Student Knowledge of Social Studies

While the National Council for Social Studies has established high standards defining effective citizenship, tests of social studies knowledge have yielded discouraging results. A report released by the Educational Testing Service in May 2012 listed three areas of concern linking poor knowledge of civics to “voting and civic engagement.” The principal concerns were:

In the most recent national assessment, only about one-quarter reached the "proficient" level, demonstrating solid academic performance.

Only 27% of fourth-graders could identify the purpose of the U.S. Constitution.
Only 22% of eighth-graders could recognize a role played by the U.S. Supreme Court.

For three successive years, the Intercollegiate Studies Institute — ISI — surveyed college students to determine the effect of college educations on civic knowledge using a sixty-question multiple-choice test of America’s history and institutions. The results are summarized below:

Freshman average in 2006 = 51.7%; freshman average in 2007 = 50.4%
Senior average in 2006 = 53.2%; senior average in 2007 = 54.2 %.

A 2009 survey conducted by the American Revolution Center revealed, among other things, "that 83% of Americans failed a basic test on the American Revolution."

The ISI was also concerned "that College-educated adults were particularly ignorant of the Founding and Civil War eras, constitutional themes, and the essential features of a market economy."

The National Assessment of Educational Progress offers sample questions that were missed by approximately 50% of 12 graders on a recent assessment. One example in economics is given below:

Which of the following is a policy tool of the Federal Reserve?

A. Raising or lowering income taxes

B . Increasing or decreasing unemployment benefits

C. Buying or selling government securities

D. Increasing or decreasing government spending

Take the five-question test at the Nation's Report site to find the answer.

Ignorance of Social Studies Is Not a Laughing Matter

Jay Leno fans are familiar with a popular segment on his show called “Jay Walking.” The segments feature Leno on the street asking people at random questions a high school graduate would be “expected” to know. Certainly the clips are edited and the people interviewed are not a representative sample. Still, the apparent ease with which poorly informed citizens are found is disturbing.

The “Jay Walking” idea has led to student projects using the same format to demonstrate and alarming lack of basic knowledge in civics.

Before laughing too hard, one might wish to take the Civic Literacy Exam offered by the Intercollegiate Studies Institute. A sample of over 2,500 Americans scores an average of 49% correct. Surprisingly, college educators scored only slightly better — 55%.

We Just Don't Seem to Like Social Studies

The facts of social studies — i.e. dates, statistics, etc. — are not generally essential to proficient knowledge of the various fields. An understanding of how governments function, the role of economics, comprehension of cultural differences, how geography relates to progress, the lessons of history, and many other broad issues enable citizens to process the events of global events.

The correct interpretation of political behavior is essential to making decisions for electing qualified officials. There is an enormous competition in the various media for divergent ideologies. Citizens who cannot assess the claims and counter-claims of candidates may be setting themselves up to be victims of their ignorance.

Position statements of the National Council for Social Studies offer numerous good points for teachers to offer to students and parents. Teachers are at the forefront of advocacy for better resources in social studies education.

Various indicators provide an unsettling profile of social studies knowledge of American students and citizens generally. Surveys and tests show that deficits in knowledge of government, economy, etc. are not limited to the uneducated. In a world that is increasingly international in scope, a citizenry composed of an educated electorate is essential.

Really Easy and Quick Science Demonstrations

Teaching science is enhanced when students have high-interest teacher demonstrations that make important science facts easier to understand.

1. Point: heat is the movement of molecules

 Procedure: put 400 ml cool water (50 F) in a beaker and an equal amount of 100 F in another beaker. While students watch, put one or two drops of food coloring into each. The food coloring in the warmer beaker will diffuse through the beaker with warm water within minutes due to the faster motion of the molecules.

2. Point: to see how colors mix to make difference colors

Procedure: cut a strip of paper towel about one inch by 12 inches. Using a blue water soluble maker (E.g.: Vis-à-Vis) and make a dark mark about one inch from one end of the strip. Suspend the paper towel in a beaker of water so that it just touches the water below the blue mark. As the water is soaked upward by capillary action, it will separate the different colors in the blue dye and move them slowly up the strip. Allow 5 to 10 minutes for the separation. Blue works best, but green and read are interesting as well.

3. Point: Effect of evaporation on cooling

Procedure: wrap the bulb of a lab thermometer in a single ply of toilet tissue. Wrap around only one or two times and wet the tissue. Note the temperature of the air in the room before beginning. Gently wave the thermometer around or back and forth, stopping every 15 seconds or so to note the temperature which should drop as water evaporates and cools the bulb. This works well when the air is dry (humidity < 50), but will usually produce results inside on any day. After two or three minutes the temperature will level off. Compare on a rainy day and the temperature drop will be less. Students can do this as a simple experiment.

4. Point: How density affects buoyancy

Procedure: pour a clear carbonated drink (like Sprite) carefully into a clear, tall drinking glass. Add about 10 fresh raisins. Initially, the raisins will tend to sink because they are denser than the drink, but as bubbles of carbon dioxide attach to the raisins, they reduce the density and cause the raisins to float to the top. The bubbles will burst at the surface and the raisins will sink again. This will continue for several minutes until the carbonation (CO2) has been lost.

5. Point: demonstrate magnetic field

Procedure: Use ceramic neodymium magnets to show how magnetism can penetrate matter. A small pair of can be obtained at stores like Walmart, some tool outlets, Radio Shack, etc. They are strong enough to separate iron from cereal (like Total) after cereal has been mashed to crumbs and added to water in a Ziploc bag. Hold the magnet against the outside surface of the mixture and tiny particles of iron will be attracted to the magnet. Neodymium magnets of about one cm diameter have a magnetic field strong enough to allow one to be placed on the back of the hand and hold on to another one on the palm of the hand. Be careful! They can snap together with such force that they can pinch! 

6. Point: The "sound" of contracting air (best in cold weather)

Procedure: Have students collect two-liter soft drink bottles -- with caps-- until each student can have one bottle for the demonstration. On a cold day -- 45 F or colder outside -- have student screw the caps on the empty bottles and walk outside. As the cold air outside cools the air in the bottles, the air in them will contract causing outside air pressure to push the sides of the plastic bottles inward creating "crackling" sounds. The contraction of the bottles will be visible as dents. When they return to the classroom, the effect will be reversed and the bottles will expand. Be sure students screw the casps on tightly.

7. Point: Observing with the ears

Procedure: Students often think that observation is done with the eyes only. Place a common object (paper clip, rock, coin, key, etc). Conceal the object in a small box or can. Ask students to try to identify the object by the sound it makes when the container is shaken or gently rotated. Call attention to the types of clues they are using to make their conclusions.