Calculating Productivity and Efficiency

Dont wanna assume anything so want to get this clear:
In your formula.. what exactly do you mean by “standard”??

Productivity = no of items produced *(std time required to produce one item)/ total time spent to produce n items
for efficiency — you would have to first decide as to what do you want to track as efficiency… is it based on time spent to produce goods or the efficiency of the output.

Does Productivity  stand  for  “Effectiveness”??

Calculating efficiency from units produced and defectives. 
 
Let Total No. of Items be:                                    N         
Let No. of Defective Items be:                              d         
Let Standard time to produce one item be:           t          
Let Total time to produce N items be:                  T
           
Now let us calculate what ratio of our production is actually usable / selleable. Let’s call it Effective Production Ratio.
 
Let Effective Production Ratio be:                        R         
Calculate Effective Production Ratio (R)   as         = (Total No. of Items – No. of Defective Items) / Total No. of Items
Therfore; Effective Production Ratio (R)                = (N-d)/N          
 
 
Productivity (P) = (Total No. of Items * Standard time to produce one item) / Total time to produce N items
                          = ( N * t ) / T
 
 
Efficiency (E)    = Productivity * Effective Production Ratio = P * R
= (Total No. of Items * Standard time to produce one item * Effective Production Ratio) / Total time to produce N items
                        = ( N * t * R ) / T
 
I used the symbols to avoid making mistakes. Excuse me if the above is a little too mathematical.

I copied this from http://www.oee.com, since your wanting to include defects into the equation this is the best way to accomplish your goal. More information at the web site, but I think this will help. In your other post you mentioned a standard, I assume this already takes into account breaks, normal tool changes, and adjustments?

Calculating OEE
The Formulas
As described in World Class OEE, the OEE calculation is based on the three OEE Factors: Availability, Performance, and Quality. Here’s how each of these factors is calculated.
Availability
Availability takes into account Down Time Loss, and is calculated as:

 Availability = Operating Time / Planned Production Time
Performance
Performance takes into account Speed Loss, and is calculated as:

 Performance = Ideal Cycle Time / (Operating Time / Total Pieces)
Ideal Cycle Time is the minimum cycle time that your process can be expected to achieve in optimal circumstances. It is sometimes called Design Cycle Time, Theoretical Cycle Time or Nameplate Capacity.Since Run Rate is the reciprocal of Cycle Time, Performance can also be calculated as:

 Performance = (Total Pieces / Operating Time) / Ideal Run Rate
Performance is capped at 100%, to ensure that if an error is made in specifying the Ideal Cycle Time or Ideal Run Rate the effect on OEE will be limited.
Quality
Quality takes into account Quality Loss, and is calculated as:

 Quality = Good Pieces / Total Pieces
OEE
OEE takes into account all three OEE Factors, and is calculated as:

 OEE = Availability x Performance x Quality

Use the K.I.S.S. Method:
Productivity = the number of units / number of units scheduled.
Efficiency = the standard / the time it actually took
with the quality efficiency you would want to take the total number defectives / by the total number of units
just my 2 cents worth.

It’s a 2 1/2 year old post. Go to Lean.org and read about OEE, it is a
real simple concept.

What is meaning of std in productivity calculatuion