QI find I have limited access to information where I work (I suspect for security reasons), but the unfortunate side effect is that I sometimes make an error because I don't have all the facts. How should someone with no clout go about trying to change company policy in order to remedy this?
ADetermine what you need, present "need to know" business cases to your boss, and document your assumptions about what to do when limits remain.
The inner game
Look at the information you need, analyzing the situation task by task. Catalog the errors you've made, looking realistically at the root causes. These may include limited information, but may also be due to factors such as simple human error. Be thorough and own up to errors that may have been avoidable so that you can be effective in making a case for needing additional information.
Then restate the situation so that instead of seeking specific information, you're articulating the questions you need to be able to answer. In this way, you open the possibility that other information sources may be able to give you the direction or insight you need.
Be sure that you understand your company's data security policy.
If you're not sure that your limited access is due to security reasons, explore whether there are other reasons, perhaps related to long-standing business processes or old company habits that may be more flexible.
Finally, get a sense of whether you have, in any way, caused any erosion of trust. Likewise, consider whether your trustworthiness may simply be untested.
To have access to sensitive information, your reputation needs to be solid, so determine if you need to do any trust-building.
The outer game
Start by building a business case for obtaining information, using a specific situation. For example: "In order to determine whether this bill should be paid, I need to have the following questions answered ... I've had to proceed without these answers, so I've made errors, which resulted in the following rework." (This also serves as useful documentation in case you're questioned about errors.) Then present this to your boss, asking for direction on how to get the information you need.
Simply taking this type of proactive approach will likely build your credibility in your boss' mind. It also provides an opportunity to have a broader discussion about the reasons for limitations on data access so that you have a clearer understanding of the organization's perspective.
Also explore whether there are training programs or any type of internal certifications that would give you higher levels of access, even within your current role. If you hear about any task forces or committees that address these issues, volunteer to participate so that you'll have some role -- often decisionmakers in organizations don't understand the grass-roots level effect, so you may be able to help ease some restrictions, especially if they aren't imposed by outside regulators.
The last word
Be direct about the effect of the information limits and be creative about ways to work with them in order to be successful in your position.