It is relatively easy to screen out the main companies in the lines of business covered by the exclusionary screens such as alcohol, gambling, tobacco, military contracting, nuclear power and firearms. The most difficult questions involve tangential businesses. Beyond the basic exclusionary areas, screening becomes more difficult. In these areas companies can have negatives or positives or both. Qualitative screens are sometimes used affirmatively.
Some institutions seek to invest in companies that advance their mission.
An environmental group might include in its investment guidelines a preference for companies selling ecologically sound products. By their nature, qualitative screens require a nuanced evaluation of a company's performance. Evaluating the relationship between a company and the environment in which it operates poses difficult questions for researchers and investors. Qualitative screening becomes harder if the companies are multi-nationals or are not subject to U.S. reporting requirements, thus limiting the information available on their operations. This type of communication is described above.