I am often asked “When is the best time to implement service integration[1]?”  Or I am told “We can’t implement service integration because we have (or have not) already multi-sourced our services”
There is no simple answer to the question; but there is a simple answer to the assertion – “Yes, you can”. 
Any implementation will be affected by the context in which it happens.   Service integration is no different.
If you are planning for a multi-sourced environment, you have the opportunity to make a strategic decision about your target service integration function.   An early decision is whether to outsource, or run it in-house (see my recent blog).  If you decide to outsource it you need to consider what your retained IT organisation will look like.  Will it be ‘thick’ and include many of the managerial elements of service integration?  This will leave the service provider with the more operational parts.  Or will it be ‘thin’? Such a retained organisation is limited to those areas that for legal, commercial or policy reasons must stay in-house.
If you are already implementing multi-sourcing it is worth implementing some service integration basics.  Consideration should be given to integrated service level management & reporting, transition planning, a unified service catalogue, capacity management and other core service management processes.  While many of these may already been in place, they need to be implemented in an end-to-end way; enabling services to be properly monitored and managed.  This in turn enables the services to be mapped to the business outcomes they support;  their true value can then be measured.
If you have already implemented a multi-sourcing strategy then you need to consider whether the lack of service integration is affecting service quality.  
 If the impact is assessed as temporarily acceptable, or if an ‘in-flight’ implementation is too risky; then you might choose to proceed with a planned implementation (defining a service integration model based on a thick or thin model, and then planning for implementation). 
Alternatively, if significant impacts are identified, you should consider the phased implementation of service integration basics.
Whatever approach you choose a thorough analysis of required and existing skills, capabilities and competencies is a must.  Service integration roles require highly developed interpersonal skills; I will develop this theme in my next blog.

[1] Defined as the management of separately contracted and supplied IT services to ensure they consistently work together to deliver business benefits.