The scale I’m about to define comes from one insight about human organizations. Teams, in general, have four categories into which a person’s contribution can fall: dividers, subtracters, adders, and multipliers. Dividers are the cancerous people who have a broad-based negative effect on productivity. This usually results from problems with a person’s attitude or ethics– “benign incompetence” (except in managers, whose job descriptions allow them only to be multipliers or dividers) is rarely enough to have a “divider” effect. This is an “HR issue” (dividers must improve or be fired) but not the scope of this professional-development scale, which assumes good-faith and a wish for progress. Subtracters are people who produce less than they cost, including the time of others who must coach and supervise them. As a temporary state, there’s nothing wrong with being a subtracter– almost every software engineer starts out his career as one, and it’s common to be a subtracter in the first weeks of a new job. Adders are the workhorses: competent individual contributors who deliver most of the actual work. Finally, multipliers are those who, often in tandem with “adder” contributions, make other people more productive. In many industries, being a multiplier is thought to be the province of management alone, but in technology that couldn’t be farther from the truth, because architectural and infrastructural contributions (such as reusable code libraries) have a broad-based impact on the effectiveness of the entire company.