diff --git a/src/app/credExplorer/App.js b/src/app/credExplorer/App.js
index 8ed7770..8bb955a 100644
--- a/src/app/credExplorer/App.js
+++ b/src/app/credExplorer/App.js
@@ -10,6 +10,8 @@ import {Graph} from "../../core/graph";
 import {pagerank, type PagerankResult} from "../../core/attribution/pagerank";
 import {PagerankTable} from "./PagerankTable";
 import type {PluginAdapter} from "../pluginAdapter";
+import {type EdgeEvaluator} from "../../core/attribution/pagerank";
+import {WeightConfig} from "./WeightConfig";
 
 type Props = {};
 type State = {
@@ -24,6 +26,7 @@ type State = {
     |},
     +pagerankResult: ?PagerankResult,
   |},
+  edgeEvaluator: ?EdgeEvaluator,
 };
 
 const REPO_OWNER_KEY = "repoOwner";
@@ -36,6 +39,7 @@ export default class App extends React.Component<Props, State> {
       repoOwner: "",
       repoName: "",
       data: {graphWithMetadata: null, pagerankResult: null},
+      edgeEvaluator: null,
     };
   }
 
@@ -47,6 +51,7 @@ export default class App extends React.Component<Props, State> {
   }
 
   render() {
+    const {edgeEvaluator} = this.state;
     const {graphWithMetadata, pagerankResult} = this.state.data;
     return (
       <div>
@@ -82,20 +87,14 @@ export default class App extends React.Component<Props, State> {
           <br />
           <button onClick={() => this.loadData()}>Load data</button>
           <button
-            disabled={graphWithMetadata == null}
+            disabled={graphWithMetadata == null || edgeEvaluator == null}
             onClick={() => {
               setTimeout(() => {
-                if (graphWithMetadata == null) {
-                  throw new Error(
-                    "graphWithMetadata: " + String(graphWithMetadata)
-                  );
+                if (graphWithMetadata == null || edgeEvaluator == null) {
+                  throw new Error("Unexpected null value");
                 }
                 const {graph} = graphWithMetadata;
-                const edgeWeight = (_unused_Edge) => ({
-                  toWeight: 1,
-                  froWeight: 1,
-                });
-                const pagerankResult = pagerank(graph, edgeWeight, {
+                const pagerankResult = pagerank(graph, edgeEvaluator, {
                   verbose: true,
                 });
                 const data = {graphWithMetadata, pagerankResult};
@@ -120,6 +119,7 @@ export default class App extends React.Component<Props, State> {
           ) : (
             <p>Graph not loaded.</p>
           )}
+          <WeightConfig onChange={(ee) => this.setState({edgeEvaluator: ee})} />
           <PagerankTable
             graph={graphWithMetadata ? graphWithMetadata.graph : null}
             adapters={graphWithMetadata ? graphWithMetadata.adapters : null}
diff --git a/src/app/credExplorer/WeightConfig.js b/src/app/credExplorer/WeightConfig.js
new file mode 100644
index 0000000..bf7c832
--- /dev/null
+++ b/src/app/credExplorer/WeightConfig.js
@@ -0,0 +1,184 @@
+// @flow
+
+import React from "react";
+
+import {
+  type EdgeAddressT,
+  type NodeAddressT,
+  EdgeAddress,
+  NodeAddress,
+} from "../../core/graph";
+
+import {type EdgeEvaluator} from "../../core/attribution/pagerank";
+import {byEdgeType, byNodeType} from "./edgeWeights";
+
+// Hacks...
+import * as GithubNode from "../../plugins/github/nodes";
+import * as GithubEdge from "../../plugins/github/edges";
+import * as GitNode from "../../plugins/git/nodes";
+import * as GitEdge from "../../plugins/git/edges";
+
+type Props = {
+  onChange: (EdgeEvaluator) => void,
+};
+
+type UserEdgeWeight = {|+logWeight: number, +directionality: number|};
+type UserNodeWeight = number /* in log space */;
+
+const defaultEdgeWeights = (): Map<EdgeAddressT, UserEdgeWeight> =>
+  new Map()
+    .set(GithubEdge._Prefix.authors, {logWeight: 0, directionality: 0.5})
+    .set(GithubEdge._Prefix.mergedAs, {logWeight: 0, directionality: 0.5})
+    .set(GithubEdge._Prefix.references, {logWeight: 0, directionality: 0.5})
+    .set(GithubEdge._Prefix.hasParent, {logWeight: 0, directionality: 0.5})
+    .set(GitEdge._Prefix.hasTree, {logWeight: 0, directionality: 0.5})
+    .set(GitEdge._Prefix.hasParent, {logWeight: 0, directionality: 0.5})
+    .set(GitEdge._Prefix.includes, {logWeight: 0, directionality: 0.5})
+    .set(GitEdge._Prefix.becomes, {logWeight: 0, directionality: 0.5})
+    .set(GitEdge._Prefix.hasContents, {logWeight: 0, directionality: 0.5});
+
+const defaultNodeWeights = (): Map<NodeAddressT, UserNodeWeight> =>
+  new Map()
+    .set(GithubNode._Prefix.repo, 0)
+    .set(GithubNode._Prefix.issue, 0)
+    .set(GithubNode._Prefix.pull, 0)
+    .set(GithubNode._Prefix.review, 0)
+    .set(GithubNode._Prefix.comment, 0)
+    .set(GithubNode._Prefix.userlike, 0)
+    .set(GitNode._Prefix.blob, 0)
+    .set(GitNode._Prefix.commit, 0)
+    .set(GitNode._Prefix.tree, 0)
+    .set(GitNode._Prefix.treeEntry, 0);
+
+type State = {
+  edgeWeights: Map<EdgeAddressT, UserEdgeWeight>,
+  nodeWeights: Map<NodeAddressT, UserNodeWeight>,
+};
+
+export class WeightConfig extends React.Component<Props, State> {
+  constructor(props: Props): void {
+    super(props);
+    this.state = {
+      edgeWeights: defaultEdgeWeights(),
+      nodeWeights: defaultNodeWeights(),
+    };
+  }
+  render() {
+    return (
+      <div style={{display: "flex", flex: 1}}>
+        <EdgeConfig
+          edgeWeights={this.state.edgeWeights}
+          onChange={(ew) => this.setState({edgeWeights: ew}, () => this.fire())}
+        />
+        <NodeConfig
+          nodeWeights={this.state.nodeWeights}
+          onChange={(nw) => this.setState({nodeWeights: nw}, () => this.fire())}
+        />
+      </div>
+    );
+  }
+
+  componentDidMount() {
+    this.fire();
+  }
+
+  fire() {
+    const {edgeWeights, nodeWeights} = this.state;
+    const edgePrefixes = Array.from(edgeWeights.entries()).map(
+      ([prefix, {logWeight, directionality}]) => ({
+        prefix,
+        weight: 2 ** logWeight,
+        directionality,
+      })
+    );
+    const nodePrefixes = Array.from(nodeWeights.entries()).map(
+      ([prefix, logWeight]) => ({prefix, weight: 2 ** logWeight})
+    );
+    const edgeEvaluator = byNodeType(byEdgeType(edgePrefixes), nodePrefixes);
+    this.props.onChange(edgeEvaluator);
+  }
+}
+
+class EdgeConfig extends React.Component<{
+  edgeWeights: Map<EdgeAddressT, UserEdgeWeight>,
+  onChange: (Map<EdgeAddressT, UserEdgeWeight>) => void,
+}> {
+  render() {
+    const controls = [];
+    for (const [key, currentValue] of this.props.edgeWeights.entries()) {
+      controls.push(
+        <label style={{display: "block"}} key={key}>
+          <input
+            type="range"
+            min={-10}
+            max={10}
+            step={0.1}
+            value={currentValue.logWeight}
+            onChange={(e) => {
+              const value: number = e.target.valueAsNumber;
+              const edgeWeights = new Map(this.props.edgeWeights);
+              const oldValue = edgeWeights.get(key);
+              if (oldValue == null) {
+                throw new Error(key);
+              }
+              edgeWeights.set(key, {...oldValue, logWeight: value});
+              this.props.onChange(edgeWeights);
+            }}
+          />{" "}
+          {formatNumber(currentValue.logWeight)}{" "}
+          {JSON.stringify(EdgeAddress.toParts(key))}
+        </label>
+      );
+    }
+    return (
+      <div>
+        <h2>Edge weights (in log space)</h2>
+        {controls}
+      </div>
+    );
+  }
+}
+
+class NodeConfig extends React.Component<{
+  nodeWeights: Map<NodeAddressT, UserNodeWeight>,
+  onChange: (Map<NodeAddressT, UserNodeWeight>) => void,
+}> {
+  render() {
+    const controls = [];
+    for (const [key, currentValue] of this.props.nodeWeights.entries()) {
+      controls.push(
+        <label style={{display: "block"}} key={key}>
+          <input
+            type="range"
+            min={-10}
+            max={10}
+            step={0.1}
+            value={currentValue}
+            onChange={(e) => {
+              const value: number = e.target.valueAsNumber;
+              const nodeWeights = new Map(this.props.nodeWeights);
+              nodeWeights.set(key, value);
+              this.props.onChange(nodeWeights);
+            }}
+          />{" "}
+          {formatNumber(currentValue)}{" "}
+          {JSON.stringify(NodeAddress.toParts(key))}
+        </label>
+      );
+    }
+    return (
+      <div>
+        <h2>Node weights (in log space)</h2>
+        {controls}
+      </div>
+    );
+  }
+}
+
+function formatNumber(n: number) {
+  let x = n.toFixed(1);
+  if (!x.startsWith("-")) {
+    x = "+" + x;
+  }
+  return x.replace("-", "\u2212");
+}