Pulleys: Why would my calculated work output be higher than my work input?

[veganazi]

Homework Statement

The experiment in my Physics lab today was to determine the mechanical advantage and efficiency of various pulley systems. My calculated work output is higher than my work input, which is causing an abnormally high value for efficiency, and I am attempting to find the source of error. I have attached my data tables and a copy of the lab procedure.

Homework Equations

work output = (weight of load) * (height lifted)
work input = (force measured) * (distance moved)

The Attempt at a Solution

I guess it would be error in measurement, though I am unsure of how this could have happened.

 

[gneill]

Did you remember to include the mass of any pulleys that moved along with the load in the total load mass? (See step 7 instructions).