I am setting up something like an employee suggestion scheme using a proprietary system made available under license by an independent provider on their servers. We develop the feedback survey design which the service provider will implement and they will give us a URL for employees to use to access it. An employee might legitimately make more than one response if there are several issues they want to comment on and we want as many valid responses as possible.
The survey tools include things like graphical elements that can be dragged around a chart to register an opinion so it is more than just check boxes, radio buttons and text fields. I'm not into web coding and wouldn't be told how it is implemented even if I could understand it as it's all valuable intellectual property. The system is designed to encourage responses so it is very open and it is anonymous as an absolute matter of policy.
We are concerned that an employee wanting to make a point might get friends and family to access the survey and submit responses on their behalf, to emphasise something. If they can see the URL, either in the link they are given to get to the survey or in the browser window when they get there, they can just copy that to other people.
Without using information that would identify the respondent, as this is against the service provider's policy, we would like to make sure that at least the bulk of responses are from staff even if we can't lock it down 100%.
Staff can be directed to the survey via email or on the intranet, whichever we choose.
Is there something I could suggest to the service provider or anything we could do locally that would prevent the staff from finding the URL or fix it so that they could only access the survey from a work computer?
I am just looking for a strategy to suggest as I realise a complete solution isn't possible with so little detail about the employer's and service provider's systems.
We don't want it indexed by search engines so all the things people worry about affecting search ranking aren't a problem here.