254 WEATHER, CLIMATE, AND SOCIETY VOLUME 3 A Kaleidoscope of Understanding: Comparing Real with Random Data, Using Binary-Choice Items, to Study Preservice Elementary Teachers’ Knowledge of Climate Change* DOUGLAS HAYHOE Department of Education, Tyndale University College, Toronto, Ontario, Canada SHAWN BULLOCK Faculty of Education, University of Ontario Institute of Technology, Oshawa, Ontario, Canada KATHARINE HAYHOE Department of Geosciences, Texas Tech University, Lubbock, Texas (Manuscript received 24 May 2011, in final form 9 October 2011) ABSTRACT The authors used a 59-item survey to probe the understanding of climate change by 89 Ontario preservice teachers. The study investigated the usefulness of comparing real survey data from closed, binary choice items, with randomly generated data. Climate change was chosen to be the topic because it is a new emphasis in K–12 science curricula. If teachers had answered the survey randomly, according to Monte Carlo simulations, a normal distribution would result, with 56 of the 59 items answered correctly by 40%–60% of the respondents. A bimodal distribution resulted, however, with 34 items answered correctly by more than 60% and 18 items by less than 40%. Apparently, the teachers knew a lot about climate change, but also had many misconceptions, some identified here for the first time. Item discrimination indices and correlation coefficients, however, were the same for the real versus Monte Carlo data, suggesting that preservice teachers’ knowledge was a ‘‘kaleidoscope of understanding,’’ rather than a coherent picture. This may be because their understanding of climate change came primarily from unconnected sources in the media, or because climate change science involves many different fields of study including astronomy, biology, chemistry, ecology, oceanography, and physics. In conclusion, the analysis herein demonstrates the benefit of comparing real and random data for binary-choice item surveys in multidiscipline topics such as climate change. For those interested in climate change education, these results suggest the importance of emphasizing the difference between reliable and unreliable sources of information and giving careful attention to how to draw on concepts from different scientific fields. 1. Introduction a. Background A large body of research has focused on the understanding of scientific concepts by students and teachers. * Supplemental information related to this paper is available at the Journals Online Web site: http://dx.doi.org/10.1175/ 2011WCAS1100021.s1. Corresponding author address: Dr. Douglas Hayhoe, Tyndale University College, 25 Ballyconnor Court, Toronto ON M2M 4B3, Canada. E-mail: dhayhoe@tyndale.ca. DOI: 10.1175/WCAS-D-11-00021.1 Ó 2011 American Meteorological Society Probes used in these studies included open-ended questionnaires, concept maps, and interviews, as well as closed-ended true–false or agree–disagree questionnaires, five-point Likert-scale questionnaires, and multiple-choice questionnaires. In previous informal research, we used open-ended focus group interviews and closed-ended, multiple-choice ‘‘conceptests.’’ We gradually realized, however, when working with multidisciplinary topics such as climate change, that binary-choice item questionnaires offer some advantages that multiple-choice ones do not. With regard to the topic we studied, the province of Ontario where we undertook our research is increasingly focusing on environmental education. Climate change, in particular, occupies an important place in the science curriculum. A good curriculum does not necessarily result OCTOBER 2011 HAYHOE ET AL. in effective teaching, however, especially if the teachers have never been educated in the topic. What is needed to complement this is an aggressive education program for teachers. To measure the effectiveness of any such program, we created a 59-item binary choice questionnaire of key climate change concepts and administered it to 89 preservice elementary teachers at two Ontario institutions. The results have given us a baseline of current understandings and misconceptions held by Ontario preservice elementary teachers, as well as validated the statistical method we used to analyze the data. b. Literature review Research on the understanding of climate change has been conducted with students in Australia, Canada, Britain, Greece, Norway, Sweden, Turkey, the United Kingdom, and the United States.1 Several studies have been reported on in the Bulletin of the Atmospheric Meteorological Society,2 as well as in other journals.3 Table 1 lists misconceptions identified in these studies, classifying them into four categories. Many surveys have also been conducted with teachers in different countries, including preservice elementary teachers.4 The survey being reported here may be the first done with preservice elementary teachers in Canada. 2. Methodology a. Concepts tested We relied on several research sources when developing our diagnostic instrument (e.g., Boyes and Stanisstreet 1993; Cordero et al. 2008) but also incorporated climate concepts from relevant curriculum documents for Ontario and Canada,5 international documents such as the IPCC Fourth Assessment Report, and our own experience.6 Climate change surveys often focus on recent 1 In a longer form of this paper, we have catalogued the results of over 40 research reports on this topic. 2 Morgan and Moran 1995; Gowda et al. 1997; Cordero et al. 2008. 3 For example, Andersson and Wallin 2000; Boyes and Stanisstreet 2001; Reynolds et al. 2010; Sterman and Sweeney 2007. 4 For example, Dove 1996; Ekborg and Areskoug 2006; Groves and Pugh 1999; Kisoglu et al. 2010; Matkins and Bell 2007. 5 The 2007 Ontario Curriculum Science and Technology Grades 1–8; The 2008 Ontario Curriculum Science Grades 9–12; The 1996 Pan-Canadian Common Framework of Science Learning Outcomes K to 12. 6 One of the authors is a recognized climate scientist. The other two are experienced science and physics teachers, as well as science education researchers. Two of the authors were part of a three-author team that wrote the Grade 10 Unit, Climate Change, for a well-known student textbook used across Ontario, called Nelson Science 10. 255 changes in Earth’s climate system resulting from human impacts. In our educational work, however, we realized that long-range changes, such as the 100 000-yr cycle, were not understood well; and thus many teachers were not able to differentiate between natural and anthropogenic causes of climate change. Therefore, 15 of the 59 items in our survey addressed long-range concepts related to Earth’s climate. (The questionnaire is included in the supplemental material available at the Journals Online Web site: http://dx.doi.org/10.1175/2011WCAS1100021.s1.) Although many of the 59 items had been addressed before, for 15–20 of them we had no previous data. Even for items addressed previously, researchers often reported significantly different results. b. Binary-choice format We initially developed a multiple-choice questionnaire and field-tested it with Ontario teachers. The results were interesting. Unlike other multiplechoice diagnostics we had used with Ontario teachers and students, for the climate change diagnostic only two of the four options were used for most items. Teachers either chose the correct answer or the same incorrect answer. This suggested that we employ binary choice items rather than four-distracter items. In fact, Haladyna (2004), in his well-known book, Developing and Validating Multiple-Choice Test Items, had suggested that multiple-choice questions work best with only two distracters. We found we only needed one. Having chosen binary-choice items, we initially followed the lead of previous researchers on climate change understanding, who used true–false or agree–disagree items, and sometimes a Likert scale response (i.e., strongly agree, somewhat agree, not sure, somewhat disagree, strongly disagree). After further field testing, we had misgivings that a ‘‘positive statement bias’’ might be attached to agree–disagree or true–false statements. Teachers with little science background might err on the ‘‘agree’’ or ‘‘true’’ side when confronted with a statement that sounded scientific. We therefore reworded each item to make it as neutral as possible, as follows: 10. If there was no greenhouse effect a. life on Earth would be drastically different b. life on Earth would be much the same as it is today Each question begins with a statement that is completed by either option A or option B. The two options have approximately the same length. Option A is correct approximately half the time. Only 3 of the 59 items (e.g., question 10 above) used the word ‘‘not’’ or ‘‘no.’’ Such safeguards are discussed more thoroughly in Haladyna (2004). 256 WEATHER, CLIMATE, AND SOCIETY VOLUME 3 TABLE 1. Summary of misconceptions held by people regarding climate change. Evidence for climate change Climate means pretty much the same thing as weather Earth’s temperature has risen 28 or 38C over the past century Gowda et al. (1997); Papadimitriou (2004); Reynolds et al. (2010) Bostrom et al. (1994); Gowda et al. (1997); Reynolds et al. (2010) Causes and processes of climate change The ozone hole and UV radiation helps cause the greenhouse effect Skin cancer is caused by the greenhouse effect Greenhouse gases are confined to a thin layer high in our atmosphere The greenhouse effect is caused by earth’s atmosphere absorbing incoming solar radiation Greenhouse gases are similar in their effect to atmospheric pollutants such as aerosols If people didn’t exist there wouldn’t be a greenhouse CO2 is the most abundant greenhouse gas Boyes and Stanisstreet (1992) and many additional studies, although some recent studies suggest this view is now decreasing Jeffries et al. (2001); Reynolds et al. (2010); Kisoglu et al. (2010) Koulaidis and Christidou (1999); Gautier et al. (2006) Koulaidis and Christidou (1999); Rebich and Gautier (2005) Koulaidis and Christidou (1999); Papadimitriou (2004); Rebich and Gautier (2005) Dove (1996); Michail et al. (2007); Rebich and Gautier (2005); Summers et al. (2001) Khalid (2003) Impact of climate change The primary reason for sea level rise over the past century is the melting of ice at the poles An increased greenhouse effect will lead to a rise in the number of earthquakes Earth’s temperature will rise by 48–68C over the next 50 years Reynolds et al. (2010) Ekborg and Areskoug (2006); Groves and Pugh (1999) Bostrom et al. (1994); Gowda et al. (1997); Reynolds et al. (2010) Mitigation of climate change If CO2 production is reduced by 30%, atmospheric concentrations will start to fall The greenhouse effect is made worse by radioactive waste Increased use of nuclear power will contribute to an increased greenhouse effect The use of energy-saving light bulbs does not affect global warming c. Subjects Preservice elementary teachers enrolled in primary– junior (K–6) science methods courses at two Ontario universities in the Toronto area were invited to participate in the anonymous online questionnaire by answering it on their own time. (These teachers were enrolled in oneyear Bachelor of Education programs, consisting of educational courses at the universities and practicum sessions in schools.) While the possibility exists that some may have studied up on topics while answering the questionnaire, there was no obvious motivation for them to do so. Their participation was anonymous, they were never told their score, and they were not studying climate change at that time. Of approximately 280 preservice teachers enrolled in 8 classes, 114 participated, with 89 completing all 59 items. One-third of the participants were age 30 or older. The classes from which they were drawn were 80%–90% female and represented the cultural diversity of the greater Sterman and Sweeney (2007) Boyes and Stanisstreet (1993) Groves and Pugh (1999); Reynolds et al. (2010) Cordero et al. (2008) Toronto area. Everyone had a university degree, usually a generalist degree with little if any science at the university level. The smaller institution was a private Christian university, while the larger institution supplying the majority of subjects was a midsize public university. The survey did not ask how many university-level science courses they had taken, since demographic data collected by the universities indicated that very few had studied science at that level. Since the topic of climate change was only introduced into the Ontario secondary school science curriculum in 2007, we knew that few if any had formally studied the topic in science. Furthermore, to our knowledge, the topic of climate change is not covered in any detail in the social science courses offered at nearby universities. 3. Observations and analysis The questionnaire in the supplement includes item difficulty and discrimination indices for the 59 items, when answered by the 89 preservice elementary teachers. OCTOBER 2011 HAYHOE ET AL. 257 The item difficulty index refers to the percent of subjects answering that item correctly. To compute item discrimination indices, we subtracted the average score on that item of the bottom 27% from the top 27% of the subjects, based on their response to the entire questionnaire, and then divided by the number of subjects included in the 27% (i.e., 24 subjects). One of the concerns with a closed-ended questionnaire, especially a binary-choice one, is the role of randomness. Since few if any subjects had formally studied climate change, the possibility existed that for many items their answers would be basically random. This is where Monte Carlo simulations came in. Before drawing conclusions from the survey results, we first compared our data with randomly generated data. Only data that differed significantly from this random data will be commented on. a. Item difficulty analysis The average item difficulty index on the survey was 0.58, fairly close to an average item difficulty for randomly generated data of 0.50. Does this suggest that respondents were guessing on most of the questions? The frequency histograms for the item difficulties for real data compared with randomly generated data tell another story. Figure 1 presents the randomly generated data and Fig. 2 the real data. With randomly generated data, 95% of the items (56 of 59) have an item difficulty between 0.400 and 0.600. With real data, only 12% (7 of 59) have an item difficulty in this range. Rather, 58% (34 of 59) have an item difficulty above 0.600 and 30% (18 of 59) have an item difficulty below 0.400. The frequency histogram is strongly bimodal. This suggests that for the 34 items with a difficulty index greater than 0.600, many respondents had a good understanding about the concepts addressed, while for the 18 items with a difficulty index less than 0.400, many had misconceptions about those concepts addressed. FIG. 1. Frequency histogram of item difficulty for 59 items with 89 randomly generated responses, averaged over 10 trials. (The numbers on the x axes represent the 10% of the spread leading up to that number. For example, 28.7 of the items had an item difficulty greater than 0.50 and less than or equal to 0.60.) d d d 2) ITEMS ANSWERED CORRECTLY BY LESS THAN 30% OF RESPONDENTS Respondents had misconceptions regarding these concepts: d d 1) ITEMS ANSWERED CORRECTLY BY OVER 80% OF RESPONDENTS Although all items with difficulty index above 60% are probably significant, ones above 80% particularly stand out. Respondents overwhelming knew that . . . d d d d d d d d d weather and climate mean different things (#2; 94%) Earth’s surface gives off radiation at night (#6; 94%) carbon dioxide and methane are invisible (#10; 89%), historically Earth’s climate has varied in long cycles (#14; 92%) sea levels have varied by 5 to 10 m, not 1 m or less (#15; 84%), volcanic eruptions cause temporary climate change (#16; 85%) more atmospheric carbon dioxide increases the greenhouse effect (#27; 90%) the greenhouse effect is increased by the removal of large forests (#38; 91%). oceans and forests continually exchange CO2 with the atmosphere (#54; 88%). solar energy is concentrated in the visible, not infrared part of the spectrum (#4; 8%)7 the most common greenhouse gas is water vapor and not carbon dioxide (#8; 15%) waste heat from use of fossil fuels does not contribute to global warming (#19; 18%) when sea ice melts it does not affect the sea level of oceans (#20; 19%) radioactive waste from nuclear power does not contribute to the greenhouse effect (#28; 29%) 7 The authors now realize this is not correct. A little less than half of the sun’s energy is visible light, with about the same amount being infrared radiation and the remainder ultraviolet. See Solar Radiation and Climate Experiment, available online at the National Aeronautics and Space Administration (NASA) Earth Observatory website, accessed 23 April 2011. 258 WEATHER, CLIMATE, AND SOCIETY VOLUME 3 reactions produce carbon dioxide, but because they produce waste heat, which contributes to global warming. (Compared to greenhouse gases, waste heat from chemical and nuclear reactions has no significant effect.) Regarding item 32 above, most of the respondents were unaware that the oceans absorb most of the carbon dioxide produced by humans (something not reported on in previous research). This fact is important because it affects the acidification of the oceans and it delays the effect of carbon dioxide production on climate change. (Table 2 gives a summary of results.) FIG. 2. Frequency histogram of item difficulty for the 59 items with real responses from the 89 teacher candidates. d d d the thinning of the ozone layer has not contributed to the greenhouse effect (#29; 28%) oceans absorb most of the atmospheric carbon dioxide produced from human activities (#32; 29%) atmospheric pollutants such as dust and sulfur dioxide cause a decrease (not an increase) in Earth’s average temperature (#37; 25%) What is interesting in these results is that 82% of respondents thought that the release of waste heat from the use of fossil fuels significantly contributes to global warming (item 19 above). Perhaps this is why 71% thought that radioactive waste from nuclear reactions also contributes to global warming (item 28 above), not because nuclear b. Item discrimination analysis As mentioned earlier, the discrimination index we used equaled the average score on that item for the highest 27% of the respondents (based on their overall score) minus the lowest 27%. Since 27% of 89 respondents equals 24, we subtracted the scores of the lowest 24 from the highest 24 and divided by 24. This resulted in decimal numbers based on fractions of 24 (i.e., 3/ 24). Thus, it made sense to use intervals of 1/ 24 or 0.0417 on the frequency graphs rather than intervals of 0.100 or 0.050 (Figs. 3 and 4). An item with a high index, above 0.30 or 0.40, discriminates well between respondents who score high overall on the test and those that do not and is considered to be a good item. Items with a low index have little value in discriminating because respondents scoring high overall TABLE 2. Climate literacy misconceptions identified in this questionnaire. Misconceptions identified in the literature and corroborated in this research 1. Equatorial regions on Earth have the warmest climate because they are closest to the sun (item 2) 2. The most common greenhouse gas is carbon dioxide (item 8) 3. When polar sea ice floating in the Arctic ocean melts it causes ocean levels to rise (item 20) 4. Earth’s average temperature has risen by more than 38C over the past century (item 21) 5. Radioactive waste from nuclear power increases the greenhouse effect (item 28) 6. The thinning of the ozone layer has contributed significantly to the greenhouse effect (item 29) 7. An increase in the greenhouse effect will likely cause more skin cancer (item 36) 8. Atmospheric pollutants that are not greenhouse gases such as dust and sulfur dioxide cause an increase in Earth’s average temperature (item 37) 9. Earthquakes and tsunamis are related to global warming (item 43) 10. If the world reduced by 30% the rate at which carbon dioxide is being added to the atmosphere, the total atmospheric concentration of CO2 would soon start to go down (vs would still continue to rise) (item 51) Additional climate literacy misconceptions identified in this research 11. Most of the sun’s radiant energy is concentrated in the infrared part of the spectrum, not in the visible part (item 4) 12. The amount of energy that Earth’s system radiates into outer space every day is much less than the amount of energy it receives from the sun every day (item 5) 13. Waste heat resulting from human use of fossil fuel contributes significantly global warming (item 19) 14. Oceans only absorb a little of the atmospheric CO2 produced from human activities (item 32) 15. People in North America use more energy in residential use of electricity than in travel (item 40) 16. Over the past century, most of the heat added to Earth’s climate system because of the enhanced greenhouse has remained in the atmosphere (doesn’t go into the ocean) (item 42) 17. The idea that the world is warming at a dangerous rate is supported by approximately half of the climate scientists (vs almost all of the climate scientists) (item 49) 18. Placing large space umbrellas in orbit high above Earth’s atmosphere to block out some of the sun’s rays would not affect global warming (item 58) OCTOBER 2011 HAYHOE ET AL. FIG. 3. Frequency histogram of item discrimination for 59 items with 89 randomly generated responses, averaged over 10 trials (The number under each bar gives the frequency up to that number; i.e., 7.6 items had a discrimination index from 0.167 to 0.208, according to this Monte Carlo simulation.) on the test do little better on that item than respondents scoring low overall on the test. This assumes a strong coherence among concepts being tested, such as what you would expect in a questionnaire on Newton’s laws of force, for example.8 In this climate change questionnaire, the average item discrimination index was only 0.197. In fact, only 10 items had a discrimination index equal to or greater than 0.333, compared with 4 in the randomly generated data. The frequency histograms for the real data and randomly generated data are strikingly similar. If climate change science had the coherence of a traditional discipline such as physics, we might be worried about these results. Perhaps most of the items were not valid. There are other interpretations, however. The low number of items with high discrimination indices may imply that respondents’ knowledge came in bits and pieces (i.e., from newspapers, radio, the Internet, television newscasts programs, talking with friends), so that how they did on one item has little correlation with how they did on other items. Gowda et al. (1997) arrived at a similar interpretation in their discussion of the results of a survey on climate change with 99 American high school students. Another interpretation of our data is that climate change science, unlike physics, involves concepts drawn from many fields, such as astronomy, biology, 8 The authors did informal research using 35 item multiplechoice diagnostics of force and motion with over a hundred secondary students. The frequency histogram of the item difficulty index was not bimodal as for this questionnaire, and 16 of the 35 discrimination indices were above 0.30, in contrast to only 3 of the 35 discrimination indices being above 0.30 for randomized data. 259 FIG. 4. Frequency histogram of item discrimination for the 59 items with real responses from the 89 teacher candidates. chemistry, earth science, environmental studies, geology, and physics, and people who understand concepts well in one or two fields might not understand them well in the others. These two conclusions were further supported by the comparison of Pearson correlation coefficients for the 1772 pairs of the 59 items. As with the discrimination indices, there was little difference if any between the matrix of correlation coefficients of the real data and those of the randomly generated data. 4. Summary and conclusions A survey of the understanding of climate change concepts was undertaken with Ontario preservice teachers, most of whom had never formally studied climate change nor studied university-level science. The survey used closed, binary-choice items and led to statistically interesting results. A comparison of item difficulty indices for the real data against the randomly generated data suggested that although many teachers knew a considerable amount about climate change, they also had many misconceptions, some identified here for the first time. A comparison of item discrimination indices for the real data against the randomly generated data implied that the teachers’ knowledge was a ‘‘kaleidoscope of understanding,’’ rather than a coherent picture. This conclusion was further supported by comparing the matrices of paired Pearson correlation coefficients for the real and randomly generated data. This study demonstrated the usefulness of comparing real with randomly generated data, using closed binary-choice 260 WEATHER, CLIMATE, AND SOCIETY items for multidiscipline topics such as climate change. In future research, we plan to extend this analysis to another multidiscipline topic in Ontario’s science curriculum, Water Systems. This study also led to tentative conclusions regarding the lack of significant item discrimination indices or correlation coefficients. These may be due to the fact that the teachers’ understanding of climate change came from unconnected sources, or it may be because climate change science builds on concepts from many different fields of study. 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