Journal of Arboriculture 31(3): May 2005 141 summit also identified both a number of barriers to effective teaching and innovative and creative teaching tools. Because of the limited number of educators attending the summit, a broad mail survey effort was funded by the International Society of Arboriculture to help the society, educators, and practitioners better understand the realities and needs of our educational efforts. As part of the survey effort, a committee was formed to review and finalize a self- administered mail survey instrument, and a professional survey instrument was prepared and sent to 192 educators in universities and colleges across the United States. The survey asked questions about participants’ work duties and responsi- bilities (such as teaching in a university or 2-year college); their attitudes about the importance and adequate provision of arboricultural topics (such as fertilization, chain-saw operations, climbing, pruning, and rigging); their attitudes about the importance and adequate provision of urban forestry topics (such as land use planning, ordinances, and shade tree commissions); their ideas about important research topics; their ideas about successful teaching tools (such as internships and field studies); their attitudes about the ISA Arborist Certification program; their attitudes about institutional and organizational educational program compo- nents (such as adequate funding); and the nature of their partnerships and outside relations (such as their relationships with the green industry, municipalities, and others). Using a standard Dillman Mail Survey Technique, 136 surveys were returned for a response rate of 71%. OPERATIONALIZATION OF VARIABLES In addition to descriptive statistics, this study used five constructed variables to examine differences in attitudes among study participants on the topics of arboricultural practices, land use planning, safety, tree protection during construction, tree structure, and urban forest management. The variable “tree protection during construction” was a single 5-point Likert-type scale found in the original survey form. The variable “safety” was constructed by logically combining four 5-point Likert-type scales found in the original survey and testing with a reliability test. The scales for arboriculture practices, land use planning, and urban forest management were Likert-type composite scales and were constructed using factor analysis and reliability testing. A factor is defined as a dimension or construct that can account for the correlation among variables or items, such as multiple scales used to answer a single question (Agresti and Finley 1986). Factor analysis is a data reduction technique first developed for use in psychology. It is used to identify and group variables with common latent structures. The technique is useful for revealing patterns of interrela- tionships among variables. Through this process, factor analysis contributes to construct validity (i.e., it helps identify items that measure what they are supposed to measure). The technique detects clusters of variables (underlying dimensions), each of which contain variables that are strongly interrelated or redundant. It is most often used (as in this study) to reduce large numbers of scales to smaller, but more robust, statistically independent variables (factors) that can be used in regression and other statistical techniques (Green et al. 2000). The criteria established for the selection of factor items to be included in this study were a factor loading of 0.35 or higher; at least a 0.10 difference between the item’s loading with its factor and each of the other factors; each factor including at least three items; and the ability to logically interpret and name the resulting factor (Green et al. 2000). The Likert-type scales discussed below were subject to principal component analysis using the varimax rotation program available in SPSSX. Reliability analysis measures the extent to which a composite scale is able to measure a concept with similar results, in repeated applications, over different scale items (Green et al. 2000). High reliability increases the internal consistency of the construct. For this study, Cronbach’s alpha, which range from 0 to 1.0, was used as a measure of the reliability of composite scales. All five of these scales were used as dependent variables in a chi-square test of independence. Independent variables included in the chi-square test were Certified Arborist (yes or no); length of time in profession; residence (self reported: city, suburb, town); state (U.S. West, Midwest, South, and East); worked as an arborist (yes or no); and worked as an urban forester (yes or no). One criteria for the selection of independent variables was provision of enough cases for statistical analysis. Arboricultural Practices To assess differences in respondents’ attitudes about arboricultural practices, a composite scale was used. Initially, 11 scales were used to answer one question (“Please circle the number that best describes your opinion of their importance in arboriculture education”) using a 5-point Likert-type scale format (1 = very unimportant, 5 = very important). One component or dimension was extracted and used to reflect the respondents’ attitude about arboricultural practices. The arboricultural practices variable was constructed from seven original survey scales: rigging, tree removal, cabling and bracing, lightening protection, tree climbing techniques, chain-saw operations, and heavy equipment operations. This factor had an eigenvalue of 4.81, explained 62% of the variation in the matrix, and had an acceptable alpha of 0.89. Land Use Planning To assess differences in respondents’ attitudes about land use planning a composite scale was used. Initially, 19 scales ©2005 International Society of Arboriculture
May 2005
| Title Name |
Pages |
Delete |
Url |
| Empty |
Ai generated response may be inaccurate.
Search Text Block
Page #page_num
#doc_title
Hi $receivername|$receiveremail,
$sendername|$senderemail wrote these comments for you:
$message
$sendername|$senderemail would like for you to view the following digital edition.
Please click on the page below to be directed to the digital edition:
$thumbnail$pagenum
$link$pagenum
Your form submission was a success.
Downloading PDF
Generating your PDF, please wait...
This process might take longer please wait
