What are the disadvantages of using grid analysis to make decisions?

Grid analysis can be inaccurate if each consequence is not weighted properly. This can occur when the decision makers are not able to accurately measure the severity of a consequence, or when a decision maker changes weights to reflect their preferred course of action. It is also possible that the grid analysis will fail if all of the possible consequences are not considered. In any case, grid analysis is a tool, and cannot be 100 percent accurate.

only #2 represents an object at rest on a table.

in #1, there is no normal force due to the table; the object is accelerating downward.

in #3, the vertical forces are not balanced; the object is accelerating downward.

in #4, neither the vertical nor the horizontal forces are balanced. the object is accelerating upwards and to the right.