The last stage of the PPDAC process is that of reaching conclusions based upon the analyses conducted, and communicating these to others. Note that implementation of findings (e.g. actually proceeding with building a bypass, designating an area as unfit for habitation, or implementing a vaccination programme) does not form part of this model process, but lies beyond its confines.
“The purpose of the Conclusion stage is to report the results of the study in the language of the Problem. Concise numerical summaries and presentation graphics [tabulations, maps, geovisualizations] should be used to clarify the discussion. Statistical jargon should be avoided. As well, the Conclusion provides an opportunity to discuss the strengths and weaknesses of the Plan, Data and Analysis especially in regards to possible errors that may have arisen” Mackay and Oldford (2000)
For many problems treated in spatial analysis this summary is sufficient. For others the conclusions stage will be the start of additional work: re-visiting the problem and iterating the entire process or parts of the process; a new project; implementing proposals; wider consultation, such as public participation GIS (PPGIS, Communityviz), Geoweb applications (such as Digital globes and StreetView) and participatory 3D modeling (P3DM); and/or the development of models that help to understand or explain the observations, guide future data gathering, and predict data values at locations/times not included within the analysis.