Relative Importance Index Value Research Articles

An evaluation of waste control measures in construction industry in Nigeria

Improper control of materials during different stages of construction has caused waste and associated environmental problems. Hence, this research assesses the forms, causes and factors incidental to waste and measures to effectively control construction waste. It is shown that among the factors incidental to waste, last minute client requirement was ranked highest as the factor that leads to design variation with relative importance index value of 3.97; cost of construction materials was ranked highest as a factor that affects selection of construction materials with relative importance index value of 4.05, and construction cost was ranked highest as the factor that leads to construction method with relative importance index value of 3.86. The research also showed that most of the firms do not calculate waste indices which could assist them to determine the amount of waste that could be generated on sites. Sorting exercise that could help firms to identify economy advantage associated with the waste streams is not adequately carried out. It was also discovered that most firms do not incorporate “waste management plan” into the collection of documents that are required of contracting firms during tendering process. To control waste, designers should be able to co-ordinate dimensions between materials specified during design and those procured for use at sites. There is need to allow proper control in the handling, storage and use of materials on site. Also, “waste management plan” should be incorporated as one of the documents dearly expected to be submitted by contracting firms during tendering process. Key words: Construction processes, waste, factors, effects, control measures.

Element category importance in conjoint analysis: Evidence for segment differences

Conjoint measurement is a popular research tool that uses experimentally designed combinations of concept elements (phrases, pictures), obtains consumer reactions to these combinations, and then employs statistical modelling (eg regression analysis) to understand the drivers of concept acceptance. The elements used in conjoint analysis can be classified into categories or buckets of like-minded statements, such as benefits, brands, heritages, mode of action, etc. This paper introduces the concept of the relative importance index (RII), for categories comprising different numbers of elements (verbal or visual descriptors of a concept). This index is the proportion of the total sum of squares of individual utilities attributable to each category. The RII value can be further normalised by dividing by the number of elements within the category to estimate the importance of each category normalised for the number of concept elements. Categories exhibit different importance. This study presents empirical analyses of 12 studies, each with more than ten categories, and more than 100 concept elements. Segmentation of respondents based upon the pattern of element impacts often shows dramatic segment differences in this RII index, suggesting different product development and communication strategies.

Monthly and Size-Related Changes in the Diet of Rainbow Trout in Lake Oahe, South Dakota

ABSTRACT We analyzed the food habits of rainbow trout (Oncorhynchus mykiss) from Lake Oahe, South Dakota, from May through September, 1993–1994. Rainbow trout were captured in surface, suspended and bottom monofilament gill nets. Diets were analyzed using the relative importance index (RI). Composition of the diet differed among months and among size categories of rainbow trout. Greatest RI values for zooplankton prey occurred during May, July and August. Terrestrial invertebrates had the highest RI value during June and September. Overall, RI values for aquatic macroinvertebrates and rainbow smelt (Osmerus mordax) were lower than the other two prey categories. Zooplankton were the most important prey for rainbow trout < 330 mm and decreased in importance as rainbow trout increased in length. Rainbow trout between 330–459 mm fed predominantly on terrestrial invertebrates. Rainbow smelt were incorporated into the diet of rainbow trout between 201–330 mm and increased in importance as rainbow trout length i...