When not to outsource your service or process?
Clearly anything that is not core to your business can be outsourced - it is upto you to define what is core service to your business and what is not.
As an example, One company believes the helpdesk is core to their business while another company does not believe the helpdesk is core to their culture and they go ahead and outsource it to IBM completely.
Mark Egan, ex-CIO of Symantec once said, “Help desk department is the internal facing ambassadors - they are core to the success of the employees productivity - I would not outsource it”.
Would you outsource your finance department? Probably not. That is one of your core process. How about Datacenter monitoring? Probably yes - that is not one of your core process/service and you might as well outsource.
We did not talk about the risk - overall risk is ‘ownership’ - internal staff tend to own the process/service and try to resolve it with process maturity while an outsourced vendor cannot offer the ‘ownership’ but can offer accountability.
Bottomline, there is no right answer for this - you measure the risk while review your core services and then take the decision.