In recent years there has been a growing number of online user communities engaged in the creation, visualization, and use of volunteered geographic information (VGI). These data may represent an untapped resource for researchers analyzing large-area geographic phenomena such as species distributions patterns or land and resource management issues. However very few studies have used VGI for analytic research questions as little is known about the quality of these data. An understanding of the validity of VGI is a prerequisite for further exploitation of these novel data sources in research contexts. This paper looks to identify key issues related to the credibility of VGI through a critical literature review. If the measurement of data quality for volunteered geographic data can be established in a formal framework, many new sources of information that could potentially be used to answer cross-cutting geographic research questions of interest to established communities. This low cost alternative to traditional sources of data can be used for up-to-date geographic information, if the data can be trusted
