I posted a number of recent blogs on the lens model. When you need to make a judgment about something that involves uncertainty (e.g., whether to invest in a startup), you can construct a lens model to represent the indicators you think are relevant to making that decision (e.g., good team, good business plan, meeting milestones, rate of new customers, potentially profitable, etc...). You can construct a lens model for many different types of judgments.

In today's blog I want to talk about a tool you can use to create a lens model diagram. The tool is a free opensource piece of software called Graphviz. You can download Graphviz to your computer and generate high quality graph visualizations, or you can paste your graph recipes into this online tool for generating graphs. Note that the online graphs are lower resolution that what you get if you download the software.

Graphviz is software for visualing graphs that are specified using the DOT language. The DOT language only includes a few features so it is quick to get started with. Here is a recipe you can use to get started with making your own lens diagrams.

graph {
 rankdir=LR; 
 world -- indicator1[label="0.6",penwidth=3]; 
 world -- indicator2[label="0.3",penwidth=2];
 world -- indicator3[label="0.1",penwidth=1]; 
 indicator1 -- judge[label="0.6",penwidth=3]; 
 indicator2 -- judge[label="0.3",penwidth=2]; 
 indicator3 -- judge[label="0.1",penwidth=1]; 
 judge -- world[label="Accuracy"];
}

When I paste this graph recipe into the GVEdit program that comes with the Graphviz software, and hit the "Run" button, it generates this generic lens diagram:

I could, for example, modify this graph for a salary estimation problem. Say I wanted to estimate the salary of a professor in a university setting. I could identify several salary indicators such as number of publications, professorial level, teacher rating, age and other factors, and use these indicators to construct an estimate which could then be compared to the professors actual salaries to assess accuracy. It might be some such formula that is used to actually determine the professors salaries and I could be more or less calibrated to the factors involved depending on the indicators I used and whether I included and weighted each indicator properly. In the diagram above, the cue utilization validities (numbers appearing above the lines from Indicators to Judge) exactly correspond to the ecological validities of the indicators (numbers appearing above the lines from World to Indicators) which is what perfectly calibrated judgment would look like.

Researchers have been using the lens model to study judgment and decision making for over a half-century now. Lens models are probably not used as much as they could be as a strategy to deal with uncertainty. If you want to use them then you might want to have a tool that allows you to easily construct a lens model for whatever judgment or decision problem interests you. The DOT language and the Graphviz software allow you to quickly construct a lens model of that judgment problem if you so desire.