Cross-impact analysis Futures workshops Predictive analytics Failure mode and effects analysis Futures wheel Technology roadmapping Social network analysis Systems engineering Trend analysis Morphological analysis Technology forecasting Theory U Shaping alternative futures Futurists use scenarios—alternative possible futures—as an important tool. To some extent, people can determine what they consider probable or desirable using qualitative and quantitative methods. By looking at a variety of possibilities one comes closer to shaping the future, rather than merely predicting it. Shaping alternative futures starts by establishing a number of scenarios. Setting up scenarios takes place as a process with many stages, and can take place in an evidence-based manner. Scenarios can also study unlikely and improbable developments that would otherwise be ignored. However, for credibility, they should not be entirely utopian or dystopian. One of those stages involves the study of emerging issues, such as megatrends, trends and weak signals. Megatrends illustrate major, long-term phenomena that change slowly, are often interlinked and cannot be transformed in an instant. Trends express an increase or a decrease in a phenomenon, and there are many ways to spot trends. Some argue that a trend persists long-term and long-range; affects many societal groups; grows slowly; and appears to have a profound basis. A fad operates in the short term, shows the vagaries of fashion, affects particular societal groups, and spreads quickly but superficially. Futurists have a decidedly mixed reputation and a patchy track record at successful prediction. Many 1950s futurists predicted commonplace space tourism by 2000, but ignored the possibilities of ubiquitous, cheap computers. On the other hand, many forecasts have portrayed the future with some degree of accuracy. Sample predicted futures range from predicted ecological catastrophes, through a utopian future where the poorest human being lives in what present-day observers would regard as wealth and comfort, through the transformation of humanity into a posthuman life-form, to the destruction of all life on Earth in, say, a nanotechnological disaster. For reasons of convenience, futurists have often extrapolated present technical and societal trends and assumed they will develop at the same rate into the future; but technical progress and social upheavals, in reality, take place in fits and starts and in different areas at different rates. Therefore, to some degree, the field has aimed to move away from prediction. Current futurists often present multiple scenarios that help their audience envision what "may" occur instead of merely "predicting the future". They