**4. Results from a case: Driving causes to vulnerability to coastal hazards in Southeast Asia**

The literature search results in a total of 128 eligible papers. Of these, 120 are scientific articles published in academic journals and 8 are journal editorials or communications. This body of literature is statistically analysed to reveal information on the types of study undertaken, the spatial scale of analysis, country or regional focus, hazard types, disaster management phase, conceptual approach, and research methodology.

In the analyzing process, vote counting, qualitative analysis and statistical methods are employed. The selected documents are characterized in terms of the disciplinary and geographical affiliations of the authors, their epistemological approaches and methodologies, and the focus of their work within the disaster risk reduction cycle. In 128 selected articles, a total of 336 vulnerability factors and 227 recommendations are identified and analyzed.

Some of the main findings about the vulnerability are as below:


Also there are several key findings arising from this synthesis on the research communities:

A Meta-Analysis Framework and

to ensure a complete and comprehensive analysis.

**5.2 Criteria of entering meta-analysis** 

17 met the inclusion criteria.

2001).

Its Application for Exploring the Driving Causes to Social Vulnerability 137

(2001) suggest that working with more than 100 studies may be "overly ambitious", and recommend focusing the research question more tightly(Paterson, Thorne et al. 2001).

The field of Sandelowski's study was health and nursing, in which there were relatively fewer uncertainties and the topics mainly focused on the effectiveness of certain remedies, the environment around the illness and the impacts of some external factors to the therapies. For more complex issues that involve many uncertainties, more studies are required in order

Furthermore, if a "purposive sampling or saturation techniques" brought out by Booth (2001) is employed in a meta-analysis(Booth 2001), a criteria would be set up even implicitly. Then a bias in sampling would be inevitable. Although every meta-analysis has some inherent bias by virtue of the inclusion/exclusion criteria and the methods chosen to review the literature(Rosenthal and DiMatteo 2001), in this study the bias is minimized as possible. Based on the above consideration, for the process of sampling, the method of (Suri 1999) was applied. According to this method, the search for additional literature can be terminated once the stage of data-redundancy is reached where every additional case included in the synthesis is likely to tell the same story rather than provide a new

Some researchers argue that the mixing of various literature in meta-analysis can be confusing and obscure the understanding of the facts each single studies trying to tell(Guss 1995). Also meta-analysis is sometimes criticized for mixing good and bad studies together, which is known as "garbage in and garbage out(Hunt 1997)" issue (Rosenthal and DiMatteo

Although this criticism is mainly from the quantitative research field, same suspicion exists in the qualitative field. For example, in the research of Barroso et al. (2003), when taking a meta-analysis on HIV infection, around 20% are excluded(Barroso, Gollop et al. 2003). In the research of Jones (2004) on pragmatic health service, 132 papers were read in full, but only

Meta-analysis seeks to identify as many potentially relevant studies as possible that meet the research question for a given review topic. The included studies vary considerably in their objectives, methods, data and findings. Excluding some studies indicates factitious frame that restricts the boundary of researches. But in reality, along with the merging and crossing among disciplines and methodologies, it is impossible to limit the research views, thus unadvisable to set strict criteria. In fact, the criteria of goodness and badness are objective and in some sense context dependent. Different communities of researchers have different criteria of goodness and these criteria change all time. Additionally, it is with large possibility that the criteria will bring along the problem of rising bias in the meta-analysis. From the view of vulnerability research, because vulnerability is such a complex characteristic of society-economy-nature system, and is impacted by almost all aspects in this system, in part of the studies the vulnerability is expressed implicit and even equivocal, especially in qualitative studies, where the concepts, meanings and expressions are diversely. This is substantiated in the literature searching in this study. In fact among the 128 collected studies,

perspective. Preliminary content analysis was used to determine redundancy.


This work highlights the urgent need for a multi-scaled and multi-disciplined research approach that addresses the gaps between field-based case studies, larger-scale vulnerability assessments, conceptual frameworks and theory, and the implications for policy and practice.
