Hi marent1,
As I understand it, what Minitab calls its "Main effects plot" is really a line graph of your response paneled by different predictors. Those plots represent "main effects" because they're the average effects of each variable on the response ignoring (statistically) other variables. Unless you have completely balanced cell sizes (and thus have an orthogonal design with respect to every combination of factors) running an analysis in Fit Model with all your potential factors (as others have suggested here) will give a different result from the "main effects" plot I believe you're looking for (due to adjustments in the Least Sq Means).
I have a few suggestions:
1. Use Analyze > Fit Y by X
Fit Y by X will always "ignore" the levels of other factors when calculating means and plotting the results of one factor. In your case, you would put in your response (%Label Claim) as Y, and all your potential factors in as X. When you click "OK" JMP will produce completely separate outputs for each factor. To get a representation of the mean differences to allow you to scan across for differences, Click the Red Triangle and use Means/Anova. Since you will have many outputs, you will probably want to broadcast the command; hold down the control key first, then click the Red Triangle and select Means/ANOVA. Let go of the control key after you have made your selection (you will use command if you're on the mac). This will broadcast the command to every other output in that window. Here's what this will look like (after hiding the statistical output):
This isn't exactly like what Minitab will produce, and it's a bit harder to scan across using the mean diamonds than lines (even though the former gives more information). Rather than use Means/Anova, you could use "Connect Means" under the Red Triangle > Display Options. I would also turn off the points (also under the Red Triangle > Display Options). This will produce something a bit closer:
(I also used "Arrange in Rows" for this, from the topmost Red Triangle, and used 3 per row in order to see more on one screen)
2. Use Graph > Graph Builder
To make a "main effects" plot in which each the plotted effects ignore the other factors completely, you can use Graph Builder and add all the variables you want to the plot.
a. Graph > Graph Builder
b. Drag your response to Y
c. Drag your first Factor to X
d. Click the Line in the elements bar
e. In the panel on the left side, select "Confidence Interval" or "Error Bar" in the "Error Bars" drop down (if you want this)
f. Drag your next factor to the right-hand side of the labels for the first factor in the X axis (to add another panel to this graph).
g. Repeat the step above for all your factors.
h, Click Done to close the control panel
This will produce a plot like this:
Here's a very quick video showing those steps (sorry that this is silent -- I'm at a particularly loud conference).
I hope this helps!
julian