> ## Documentation Index > Fetch the complete documentation index at: https://docs.assuric.com/llms.txt > Use this file to discover all available pages before exploring further. # Causes, controls and evidence > The model behind the hazard log: how hazards, causes, controls and evidence link, the difference between copying and linking, and how to attach evidence to a control. **Quick summary** * A hazard has causes, each cause has controls, and evidence on a control supports every hazard using it. * Editing or deleting a linked cause or control changes it everywhere it's used, but a copy is independent. ## The four objects | Object | What it is | Example | | - | - | - | | Hazard | Something about your product that could lead to harm | Patient contacted on the wrong number | | Cause | A specific way the hazard could come about | Phone number entered incorrectly at registration | | Control | Something you do that reduces the cause or its effect | Phone number format validation at entry | | Evidence | Proof the control exists and works | Screenshot of the validation rule; training log | Evidence hangs off a control, not the hazard, so one piece of evidence supports every hazard where that control appears. Causes and controls go into a shared bank every hazard can draw from, whichever hazard you created them on. The Hazard Log with HAZ-029 expanded, showing the hazard, its cause CS-029 and the cause's two controls, CTRL-047 and CTRL-049, each with a paperclip evidence count ## Copy or link Pulling a cause or control from the bank offers a copy icon and a link icon. Takes the text only. * Its controls and evidence don't come with it. * Editing it later affects only this hazard. Use copy when this hazard's version will diverge, with a different owner, evidence or scope. Connects to the original. * Its mapped controls and their evidence come with it. * Editing or deleting it anywhere affects it everywhere it appears. Use link when it's the same control doing the same job, which is the normal case. The Link or copy existing Causes to this Hazard panel, filtered to Clinic Triage Assistant, with cause CS-039 showing a copy icon and a link icon at its right edge To take a cause or control out of use without losing it, [archive it](/clinical-safety/managing-hazards#archive-instead-of-deleting). ## Evidence There are 2 routes to the same evidence pop-out, behind a control's paperclip icon: Open the hazard, select the control, and click the paperclip icon. Filter by *Awaiting Evidence* to see every control marked that way, then click the paperclip icon on each. The status is set by hand, so also scan the *Evidence* column: a control marked *Done* can still show *(0)*. The Controls tab listing the controls for Clinic Triage Assistant, with their stage, responsibility and type Either way, you can add a file, a link, a note or a document already in Assuric. * Choose an existing document where there is one, so the evidence links to it instead of uploading a copy. * *Document Version* points at one specific version, so check the control still points to the current version after the document is re-approved. The Control Evidence panel for CTRL-047 with the New Evidence button and the Add from existing evidence library section with its search box and filters ## Related articles The end-to-end procedure, using the model above. Editing, archiving or deleting a shared item. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.