Dabbawalas, 3.3 Sigma

The dabbawalas have done it again. They have failed to deliver my dabba - for the fifth time since I started subscribing to their service in July.

Here are a few calculations based on a few assumptions:

Assumptions first :
1. The dabbawalas define their motto as 'delivering home cooked food to people'. Hence, if my dabba is not delivered, it is a defect.

2. The number of days when the dabba should have been delivered is approximately :  (number of months of subscription)  * 25 - ( 2 months for when my parents were in the US and for when I was on leave for my marriage) * 25 + 10 days of february. So that's 7*25 - 2*25 + 10 = 135 days.

I wasn't able to have my dabba on 5 days for the following reasons stated by the dabbawala :
1. It was raining heavily.
2. The dabba was kept in a different place and I wasn't informed
3. The dabbawala had gone to his native place.
4. There was no dabbawala available to deliver the dabba.
5. Trains were running late.

(On four of these five occasions, food was already cooked before we were intimated about the absence of their service.)

So that's 5 defects in 135 deliveries (DPU = 0.037). Considering 1 opportunity for defect, DPMO (Defects Per Million Opportunities) = 37037,corresponding to a sigma level of 3.3.

Of course, I haven't considered several service aspects such as late deliveries, handling and spillage. Although my dabba has been delivered late only 2-3 times, there has been spillage on several occasions. One one occasion, my empty dabba was delivered home two days late because one of the dabbawalas in the chain had gone to his native place.

My dabba started getting worn out within weeks of first use because of careless handling. When my mom asked them about handling and spillage, she got their standard reply, "Aisa hi hoga, hum kutch kar nahi sakte" (That's how it is going to be.  We can't do anything about it). So much for their 'vinamrata' (courtesy) that they are so proud of.

So much for their 6 sigma hype.


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P.S. : So it finally did happen! I got someone else's food inside my dabba. Go Six Sigma!!!!!!