This Lagos-based study provides an unsupervised grouping of the causes of building collapse in Lagos State Nigeria using purposively obtained data from construction professionals (n=34) in the state. Hierarchical cluster analysis technique and mean scores were used for the analyses. Findings show that the causes of building collapse in Lagos State can be statistically grouped into design and construction-related, policy-related and quality-related causes. The most important causes of building collapse under each of these groups are respectively: poor maintenance culture, change of use of building and use of substandard materials in construction. Government needs to strengthen efforts at monitoring both the design and construction of buildings, starting with fine-tuning building related policies. A holistic approach should be adopted in addressing building material counterfeiting and circulation of substandard construction materials in the study area. Keywords: Building Approval, Building Collapse, Building Failure, Cluster Analysis, Lagos State.

Debates over the preparation, use and relevance of the Bill Of Quantities (BOQ) in the construction industry have been long standing without commensurate research effort to address the problem. The objectives of this research are to determine the extent of use of the BOQ in the Nigerian construction industry, evaluate the criteria for the use/benefits of the use of the BOQ and to evaluate the factors mitigating the use of the BOQ. Data were collected through the administration of questionnaire on 53 randomly selected construction consultants. Majority of the respondents (47.2%) were quantity surveyors, 20.8% were builders, 17% were architects, 9.4% were civil engineers and 5.7% were mechanical and electrical engineers. The data collected were analysed with the Statistical Package for Social Sciences (SPSS) using descriptive statistics and analysis of variance. Key findings are that use of the BOQ constitutes 46.35% of construction professionals' overall workload, and the most important benefit of the use of BOQs in Nigeria is that they provide common bases for competitive bidding. The five most important factors mitigating the use of the BOQ at the pre-contract stage are: limitation in scope and spread of dedicated computer software for BOQ preparation, Absence/lack of implementation of legislations compelling the use of the BOQ, BOQs are not supported by emerging procurement systems, BOQs are expensive to prepare and lack of complete information on which to base the BOQ. This research provides useful information on the strength of the factors affecting the use of the BOQ at the pre-contract stage.