Outsourced development
Statement 8
We use outsourcing development because they can do it cheaper and/or faster
56% agreed. Of course this is good but it creates an extra possibility for unreliability. Or not.
With a lack of resources it is a good idea
Also with the absence of the right knowledge it is good to use external knowledge rather than trying to built up your own knowledge. Unless you have enough time and money.
One needs good specifications. The majority of specifications is dedicated to functions. It was remarkable to see
- missing requirements for reliability
- if present it is limited to life expectance of eg. 5 years
- sometimes also its expected usage of 2000 hours/year is mentioned
- and then sometimes also extended with a standard MTBF value of 10.000 hours
A lot of external developers had no clue what MTBF means, let alone the top-down.
Many top-downers had the idea that if a product consists out of 5 units and each unit has an MTBF of 10.000 hours, dan the final product has also an MTBF of 10.000 hours Every reliability engineer knows, this is nonsense.
The term MTBF is fully explained later on. In short it means that in this case 63% of this product fail within one year. If this equals the warranty period then start building up a pile of money. A lot of experts claim that failure rate and MTBF does not mean anything because reliability calculations deviate severely from practical results. And that bathtub curve. It does not exist at all. This is not true. It has a meaning but you have to use it in the right way. A cryptic saying of Relia-Easy is: "The bathtub curve does not exist because it exists". That will be covered later..
"Ho, wait a minute. You claim a 63% warranty failures. This is not possible, because we always specified that figure and in reality we never have seen so many failures during this period"
Right, but not because of the specification. The real reason is that the development made a much better product than specified. Maybe with an MTBF of 100.000 hours, 10 times better. However if the development of this product with this specification is outsourced to a company who knows what reliability is, you might end up with a product who really has an MTBF of 10.000 hours with the inevitable high warranty costs. But the product is probably cheaper. You can not blame the outsource since they made what you specified.
It also happens that the outsourced development department is requested for a reliability calculation for whatever it is worth. It is funny to see that don't do this by themselves. You ned a reliability department for this task, but if you don't have them...
Missing is the required task to test what the real reliability is for as far as possible. It is limited to test the functionality under some environmental circumstances. Or it is left to the client. See also <ST09 Reliability of suppliers>
Outsourcing is a good action. By default they become part of the company
But if you outsource take care that reliability is not a forgotten issue. The responsibility of the supplier is only limited to the defective product itself not the added costs like service or even a production stop