Should I Include Helpers in Line Efficiency Calculation?

One of our industrial engineer friends asked me this question.

I have read the line efficiency formula in your blog but I want to know that apart from operators, the helpers who are working in that particular line are not being included in calculating the line efficiency. As they are part of that line, without them for sure operators cannot achieved what they can. So it would be very helpful if you rectify my confusion.

There is no standard rule whether to add the helpers' working hours in line efficiency calculation or not. It is up to engineers, how they present the efficiency data.

I have answered this question with explanation. Go through my point of views and share your points (agree or disagree).

The formula used for calculating a line efficiency is

Line Efficiency% = (Total minutes produced by the line / Total minutes worked by labors working in the line)*100 

You can see, for calculating line efficiency, we use two data-

(1) Minutes produced (You can say standard hours produced) 

(2) Minutes worked (Total minutes worked by the employees)

Here the Produced minutes is calculated as (Style SAM * Number of units produced)

As helpers are present in the line, they have working hours. But they don't produce any minutes (or produced hours) as most cases helpers are not given defined operations. Also the kind of work they do in a sewing line, the SAM is not allocated for their helping work. Helpers are mostly involved in works such as line-loading task, moving bundle from one place to another, collecting and counting stitched garments. This task is considered as unmeasured work.

All helpers don't work on the job that can be measured.

They don't have the contribution in total minutes produced by the line (theoretically). If you consider them in efficiency calculation, you are not balancing hours produced and hours worked. You don't get true line efficiency data. Although practically they are involved in the production and assist sewing operator directly or indirectly.

If you allocate standard minutes (SAM) for the task done by a helper, then you must include that helper in efficiency calculation. Like press-man, marker man time is included in the style SAM and they are included in line efficiency.

One also needs to understand the kind of task helpers are doing on the production line.

I know many top-tier garment manufacturing companies in India and Sri Lanka who don't include helpers' working hours in line efficiency calculation. You can say helpers work is not measured.

How will you reply to his question? I would love to know your views.