A yet more complex knowledge structure appears in the analysis of tax revenues in an attempt to plot the Laffer curve for European countries in the years 1975-1982. Upon the analysis, on the two ends of the spectrum, notable examples of two countries are worth considering: Sweden and Spain. The former, with the average tax rate of 49% showed 12% decline in tax revenue, while the latter with the average tax rate of 23% experienced a remarkable increase in tax revenues of 60%. Naturally, a single item cramming all the above facts has little chance of passing the minimum information criterion. Consider then the following items intended to ensure the student’s recall the facts related to tax rate vs tax revenue relationship:

Q: What was the average tax rate in Spain 1975-1982?

A: 23%

and

Q: What was the change in the tax revenue in Spain 1975-1982?

A: 60% increase

Unfortunately, similar questions asked for Sweden do not form a coherent memory image that would allow the student recall the entire collection of information pieces that make up the understanding of the relationship illustrated by the Laffer curve. Naturally, the understanding does not need examples. The theoretical implications of marginal tax revenue might be considered as a sufficient element of understanding; however, the usefulness of facts illustrating the theory has long been appreciated in education; I will therefore present for consideration an exemplary set of items acting as an associative glue for the discussed tax revenue case:

Q: In the years 1975-1982, the average tax rate and the tax revenue in Spain and Sweden were as follows:

Spain: ...% and 60% (respectively)

Sweden: 49% and -12% (respectively)

A: 23

and in a similar way:

Q: In the years 1975-1982, the average tax rate and the tax revenue in Spain and Sweden were as follows:

...: 23% and 60% (respectively)

Sweden: 49% and -12% (respectively)

A: Spain, etc., etc.