(i.e., no backtracking). A second person may work with the observer to identify and/or photograph insects spotted by the observer. Transects should not change from year to year and ideally should sample a variety of habitats. Examples of long-running restricted searches are Art Shapiro's Butterfly Project in the US (started in 1972), and the UK Butterfly Monitoring Scheme (started in 1976). Open searches Open searches, also sometimes referred to as "checklist searches", are intended to focus on the presence and abundance of butterflies in a given area. They can be single events such as the North American Butterfly Association's July 1 and July 4 counts in Canada and the U.S. respectively, or they can be regular or ad hoc counts conducted by individuals or groups. The lack of formal structure makes them suitable for many citizen science programs. In terms of the relative outcomes or the efficacy of open vs. restricted searches, studies have shown that open searches are more likely to find a greater number of species in a given area. Royer, et al. note that one reason for this is that during an open search, the "observer is free to search out places where butterflies typically would breed or congregate" rather than follow the fixed path of a transect. Simplified butterfly assessments To promote the broad public participation in butterfly monitoring, researcher from Austria propose to combine a simplified assessment scheme on group level executed by laypeople, with detailed assessments from butterfly experts. To evaluate their approach they compared data collected by pupils with independent assessments of professional butterfly experts. Beside some identification uncertainties data collected by trained and supervised pupils were successfully used to predict the general habitat quality for butterflies. Opportunistic sightings Opportunistic or incidental sightings are a butterfly sightings that are not part of a formal count. Observers may note signal butterflies or multiple species. An example of an opportunistic sighting is observing a butterfly in garden and reporting it. Atlas projects Described as a "special type of open search", atlas projects are generally targeted at a specific geographical area such as a province or state. The goal is to assess the presence or absence of species, usually over a multi-year period. Each atlas program will design its own data requirements but as they are measuring abundance and presence, they tend to accept data from transects, counts and opportunistic sightings to build a database. The