Get Measure Using Item IDs with Number Correct and Prior Student Information

Overview

This Bayesian function should be used when:

There is prior information about a student. For example, a previously-computed priorAbility with priorUncertainty and number of days since that assessment elapsedDays.
The student has taken some number of items, each represented by an item ID.
The number of items answered correctly is known.

URL

POST /api/score/items/ids/bayes

Request

The following parameters are required in the request. An example is provided in the Code Example section.


Parameter	Type	Description
`items`	Array	Array of item objects. Each item object is a dictionary with required parameters: `itemid` String ID of item used in the request body. Must have a prefix of “Q”, “L”, or “S”. MetaMetrics will provide these IDs.
`numberCorrect`	Integer	Raw count of items answered correctly by the student.
`priorAbility`	Integer	The student’s prior ability estimate.
`priorUncertainty`	Integer	Uncertainty associated with the student’s prior ability estimate.
`elapsedDays`	Integer	Number of days since the student’s measure was last updated.

Response

This returns an object that contains the computed ability and uncertainty. See Scoring Service Response Codes for an explanation of error codes that might be returned.


Parameter	Type	Description
`ability`	Integer	The student’s new ability estimate.
`uncertainty`	Integer	Uncertainty associated with the student’s new ability estimate.
`framework`	String	Either Lexile or Quantile; framework used to produce the measure.
`apiVersion`	String	The current version number for the API.

Code Examples

The following show examples of the request followed by the response. The Python example is written for use with Python 3 and above.

import java.io.BufferedReader;
                 import java.io.IOException;
                 import java.io.InputStreamReader;
                 import java.util.HashMap;
                 import java.util.List;
                 import java.util.ArrayList;
                 import java.util.Arrays;
                 import java.util.Map;
                 import org.apache.http.HttpHeaders;
                 import org.apache.http.HttpResponse;
                 import org.apache.http.client.HttpClient;
                 import org.apache.http.client.methods.HttpPost;
                 import org.apache.http.entity.StringEntity;
                 import org.apache.http.impl.client.HttpClientBuilder;
                 
                 import org.json.JSONObject;
                 
                 
                 public class BayesItemId {
                 public static void main( String[] args )
                 {
                 try
                 {
                 // Call 8
                 
                 String baseURL = "https://scoring.lexile.com";
                 String clientId = "your_client_id";
                 String clientSecret = "your_client_secret";
                 
                 HttpClient client = HttpClientBuilder.create().build();
                 HttpPost authPost = new HttpPost(baseURL + "/authToken");
                 JSONObject jsonInput = new JSONObject();
                 jsonInput.put("clientId", clientId);
                 jsonInput.put("clientSecret", clientSecret);
                 StringEntity input = new StringEntity(jsonInput.toString());
                 authPost.setEntity(input);
                 authPost.setHeader(HttpHeaders.CONTENT_TYPE, "application/json");
                 HttpResponse response = client.execute(authPost); 
                 StringBuilder stringBuilder = new StringBuilder();
                 BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
                 String line;
                 while ((line = rd.readLine()) != null) 
                 {
                 stringBuilder.append(line);
                 }
                 JSONObject json = new JSONObject(stringBuilder.toString());
                 String token = (String) json.get("accessToken");
                 Integer expires = (Integer) json.get("expiresIn");
                 
                 
                 // 1) Basic Example
                 
                 HttpPost postItemId = new HttpPost(baseURL + "/api/score/items/ids/bayes");
                 JSONObject postData = new JSONObject();
                 postData.put("numberCorrect", 2);
                 postData.put("framework", "lexile");
                 postData.put("priorAbility", 500);
                 postData.put("priorUncertainty", 100);
                 postData.put("elapsedDays", 50);
                 JSONArray itemList = new JSONArray();
                 JSONObject item = new JSONObject();
                 item.put("id","L17075");
                 itemList.put(item);
                 JSONObject item2 = new JSONObject();
                 item2.put("id","L17076");
                 itemList.put(item2);
                 JSONObject item3 = new JSONObject();
                 item3.put("id","L17078");
                 itemList.put(item3);
                 postData.put("items", itemList);
                 
                 StringEntity itemIdInput = new StringEntity(postData.toString());
                 input.setContentType("application/json");
                 postItemId.setEntity(itemIdInput);
                 postItemId.setHeader(HttpHeaders.AUTHORIZATION, "Bearer " + token);
                 postItemId.setHeader(HttpHeaders.CONTENT_TYPE, "application/json");
                 response = client.execute(postItemId); 
                 stringBuilder = new StringBuilder();
                 rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
                 while ((line = rd.readLine()) != null) 
                 {
                 stringBuilder.append(line);
                 }
                 JSONObject output = new JSONObject(stringBuilder.toString());
                 Integer ability = (Integer) output.get("ability");
                 Integer uncertainty = (Integer) output.get("uncertainty");
                 String framework = (String) output.get("framework");
                 String apiVersion = (String) output.get("apiVersion");
                 }
                 catch(IOException e) 
                 {
                 e.printStackTrace();
                 }
                 }
                 }
                 
                 //System.out.println(stringBuilder.toString());

# Call 8
                     
                     # /authToken
                     
                     import requests
                     import json
                     
                     base_url = "https://scoring.lexile.com"
                     client_id = "your_client_id"  # replace with your provided client ID
                     client_secret = "your_client_secret"  # replace with your provided client secret
                     response = requests.post(
                     f"{base_url}/authToken",
                     data={"clientId": client_id, "clientSecret": client_secret},
                     )
                     access_token = response.json()["accessToken"]  # use in Authorization header
                     
                     # use these headers to make requests
                     headers = {
                     "Authorization": f"Bearer {access_token}",
                     "Content-Type": "application/json",
                     }
                     
                     
                     # api/score/items/ids/bayes
                     
                     # 1) Basic Example
                     data = {
                     "priorAbility": 500,
                     "priorUncertainty": 100,
                     "elapsedDays": 15,
                     "numberCorrect": 2,
                     "items": [{"id": "L17075"}, {"id": "L17076"}, {"id": "L17078"}],
                     }
                     response = requests.post(
                     f"{base_url}/api/score/items/ids/bayes", headers=headers, json=data
                     )
                     response.json()
                     # returns
                     # {
                     #    "ability": <int>,
                     #    "uncertainty": <int>
                     #    "framework": ["lexile" or "quantile"]
                     #    "apiVersion": <string>
                     # }