Once you have established the central criteria you will use in our evaluation, you will investigate your subject in terms of these criteria. In order to investigate the subject of sustainable management methods, you would more than likely have to research whether these methods stand up to the criteria you have established: wellbeing of the logging industry, cost, labor requirements, time efficiency, conservation of resources, and preservation of the old growth forests. However, library research is only one of the techniques evaluators use. Depending on the type of evaluation being made, the evaluator might use such methods as observation, field research, and analysis.
The best place to start looking for evidence is with the knowledge you already possess. To do this, you might try brainstorming, clustering, or freewriting ideas.
When you are evaluating policies, issues, or products, you will usually need to conduct library research to find the evidence your evaluation requires. It is always a good idea to check journals, databases, and bibliographies relevant to your subject when you begin research. It is also helpful to speak with a reference librarian about how to get started.
When you are asked to evaluate a performance, event, place, object, or person, one of the best methods available is simple observation. What makes observation not so simple is the need to focus on criteria you have developed ahead of time. If, for instance, you are reviewing a student production of Hamlet, you will want to review your list of criteria (perhaps quality of acting, costumes, faithfulness to the text, set design, lighting, and length of time before intermission) before attending the play. During or after the play, you will want to take as many notes as possible, keeping these criteria in mind.
To expand your evaluation beyond your personal perspective or the perspective of your sources, you might conduct your own field research. Typical field research techniques include interviewing, taking a survey, administering a questionnaire, and conducting an experiment. These methods can help you support your judgment and can sometimes help you determine whether or not your judgment is valid.
When you are asked to evaluate a text, analysis is often the technique you will use in collecting evidence. If you are analyzing an argument, you might use the Toulmin Method. Other texts might not require such a structured analysis but might be better addressed by more general critical reading strategies.