diff --git a/ldac-check.js b/ldac-check.js
index aea79bc..92d4f61 100755
--- a/ldac-check.js
+++ b/ldac-check.js
@@ -17,20 +17,46 @@ program
   .version(version)
   .argument('<path>', 'Path to the RO-Crate metadata file')
   .option('-e, --errors', 'Output errors only')
+  .option('-c, --collate', 'Collate errors and warnings')
 
   .action(main);
 
 program.parse(process.argv);
 
+
+function collate(result) {
+  const collated = {};
+  for( const k in result ) {
+    collated[k] = {};
+    result[k].map((o) => {
+      if( !(o.clause in collated[k]) ) {
+        collated[k][o.clause] = [];
+      }
+      collated[k][o.clause].push(o.entity);
+    });
+    for( const clause in collated[k] ) {
+      collated[k][clause].sort();
+    }
+  }
+  return collated;
+}
+
+
+function print_results(result) {
+    console.log(JSON.stringify(result, null, 4));
+}
+
+
 function main(cratePath, options) {
   try {
     const opt = { alwaysAsArray: true, link: true };
     const crate = new ROCrate(JSON.parse(fs.readFileSync(cratePath, 'utf8')), opt);
-    var result = LdacProfile.validate(crate);
-    if (options.errors) {
-      console.log(result.errors);
+    const result = LdacProfile.validate(crate);
+    if (options.collate) {
+      const collated = collate(result);
+      print_results(options.errors ? collated.errors : collated);
     } else {
-      console.log(result);
+      print_results(options.errors ? result.errors : result)
     }
   } catch (error) {
     if (error.code === 'ENOENT') {