CHAPTER 5 RESULTS SHOWING SCOPE AND QUALITY OF RESEARCH ON
5.5 SUMMARY AND CONCLUSIONS
gave a list of individual propositional statements (Nakhleh & Krajcik, 1994) and in this there was evidence of mixed models. To elaborate, these authors claim the list represents “a synopsis of the Brønsted-Lowry model of acids and bases found in most high-school texts” (p 1078).
However they devote a section to macroscopic properties such as taste, indicator colours, and titrations, which are not relevant to the model (see Section 3.3.3). Furthermore, they describe bases as proton acceptors, and describe OH– ions as being a typical base, yet they give NaOH as an example of a base. The problem might have arisen in the textbooks from which the statements were gleaned, rather than the researchers. Nevertheless it highlights the urgent need for textbook revision according to sound propositional knowledge. Another problem occurred with scientifically unacceptable statements being given as propositional knowledge. This problem occurred with Botton (1990) where a ‘model’ concept map indicates that strong or weak acid or bases have fixed and characteristic pH values, rather than these values being variable according to the concentration of the substances in solution. The lack of these two important components of the research (qualitative data as student quotations and propositional knowledge statements against which to evaluate these) causes concern. It can result in some researchers making claims about ‘misconceptions’ with little or no evidence to back their claims (e.g. Hand & Treagust, 1988; Demircioğlu et al., 2004; Ouertatani et al., 2007).
• The need for some sort of open-ended data collection appears to have been acknowledged.
• Both probes and propositional knowledge used in research have shown examples of hybrid models, or even scientifically unacceptable statements.
• Research is frequently reported with insufficient detail. This concerns data collection instruments, their validity and reliability, qualitative data in the form of student quotations and interpretation of these against propositional knowledge, to arrive at a difficulty description.
A wide range of research represents the body of work concerning student conceptions. These have not only been published in academic research journals, but in less formal publications which include teachers in their audience. Nevertheless, the research community needs to continue finding ways to reach a target audience of practitioners and textbook authors so as to bridge this ‘gap’ between education research findings and their application in teaching practice (Anderson, 2007).
The variety of countries from which research has been drawn is encouraging, because in order to have a Level 4 or Established classification on a four-level framework (Table 4.4) the difficulty needs to be found in multiple contexts. The challenge of publishing in English has not inhibited publication of research from non-English speaking countries. Consequently a lack of research identified from Africa and South America is probably not due to research on cohorts from these continents having been published in other languages. It is therefore more likely that students from these places have simply not been the focus of much research on student conceptual difficulties in acid-base chemistry. However, as many students from countries such as South Africa do not learn science in their mother tongue, and may experience particular difficulties in this regard (Moji, 1998; Clerk & Rutherford, 2000) this is where an important research gap exists.
The dominant age-group researched has been senior secondary school. In this regard, Laugksch (2002) analysed titles of science education postgraduate degrees awarded in South Africa over a comparable time period and showed a similar distribution of ages of student cohorts –studies being dominated by research at the secondary-tertiary interface. Future research could fruitfully investigate which alternative acid-base conceptions may have their source in teaching at elementary and junior secondary school (e.g. see de Vos & Verdonk, 1987a; Stavridou &
Solomonidou, 1998; Nelson, 2006). Moreover, the literature review in Chapter 2 found numerous studies identifying teachers’ contribution to student conceptual difficulties so
implication of conceptual difficulties at tertiary level, particularly among pre-service teachers, is critically important.
There seems little value in attempting a remediation strategy before the nature of what you will remediate is known. Where researchers glean “misconceptions” from the literature, they would do well to evaluate these claims in terms of the underlying research on which they are based.
With half of the research reports in this critique having been published in journals of international standing, and another quarter in peer-reviewed publications, it was surprising to find so many showing a low standard of research reporting. This overview and critique of research shows that most of the difficulties already reported would not be classified as Established if considered alone; this level was achieved by only one researchers’ work (Schmidt, 1991, 1995). Other studies contributed useful data, but from limited contexts.
However, in Chapter 2, when providing the motivation for a more systematic review, I noted Torgerson’s (2003) comments on the value of many smaller studies. The sum of all the research will then be considered in the next three chapters, which may enable classification of some difficulties at a higher level if the accumulative insight from several studies permits this. This task is made more difficult by poorly and under-reported research. Accordingly, results from this chapter will influence interpretation of research claims is in the following three chapters.
In particular, the importance of propositional knowledge has been underestimated by many researchers. It must be acknowledged that some authors inferred they had an ideographic rather than nomothetic viewpoint, in trying to find what students thought, rather than how well their conceptions matched those accepted scientifically (e.g. Lin & Chiu, 2007). But other researchers with a clear aim of evaluating student conceptions against those which are scientifically acceptable, do not even state the acid-base model they used for a frame of reference (e.g. Bradley & Mosimege, 1998; Demircioğlu, 2005). As a result, some of their claims about student misconceptions may be misplaced – a student might simply be using a different model as his or her frame of reference, in other words simply hold an alternative conception. A further problem of authors describing hybrid or mixed models in the propositional knowledge expected from students (e.g. Nakhleh & Krajcik, 1994; Kousathana et al, 2005) has been identified. These issues will be addressed in the next three chapters when data on individual student difficulties are analysed alongside propositional knowledge statements.
The prevalence of deficiencies in existing research shows that the abundance of advice already published with regard to research in science education, or specifically chemistry education, (e.g.
Sanders, 1993; Good, 1993a; Bunce & Robinson, 1997; de Jong et al. 2004; Eybe & Schmidt, 2001; Bodner, 2004) has not been heeded. In response, some guidelines can be emphasised to enhance the quality of future research (see Table 5.8).
Table 5.8 Guidelines for investigating the nature of student difficulties
1 Data should be collected through a variety of methods in order to satisfy the requirement of triangulation.
2 Research should start with exploratory studies using open-ended data sources. Similarly where suspected or emergent descriptions exist. This allows one project to build on another, avoiding ad-hoc isolated studies.
3 Details of research instrument(s) should be published, including questionnaires and interview protocols. With electronic publishing, such information can be made public as online supplements (e.g. Furió-Más et al., 2007).
4 Multiple-choice items are only suitable when an established description exists. These would then be useful for studies such as prevalence. They do not help to show the nature of the difficulty, unless tied to at least a second tier of explanation. Where published research is used as the base for distractors, it is important to look at the quality of the research behind the knowledge claims and their generalizability; these should not be used uncritically.
5 Both research probes and interpretation should take place within the students’ frame of reference. Ambiguous words and mixed model terminology in probes can hinder identification of difficulties.
6 Propositional knowledge to indicate the researchers’ frame of reference when interpreting students’ responses is essential.
7 Propositional knowledge needs to be verified to avoid using mixed models.
8 Conclusions should be given with enough qualitative data to show how they arose.
9 Details of student cohorts and dates of the research are necessary.
There is nothing new in the guidelines in Table 5.8, but they are focused specifically on investigating and reporting the nature of student difficulties. Therefore they are more specific than the advice given in the publications cited above. These are based on criteria given in Table 4.4 to guide classification of descriptions and the critique in this chapter. The short list given here may serve to remind future researchers in this field.
CHAPTER 6
SYNTHESIS OF STUDENT DIFFICULTIES AND PROPOSITIONAL KNOWLEDGE REGARDING SPECIES IN ACID-BASE CHEMISTRY