# Hierarchical Task Analysis (HTA): Finding Information on a Website

> **Human-Computer Interaction (HCI) — Worked Example**
>
> This article demonstrates how Hierarchical Task Analysis (HTA) can be used to break down the task of finding information on a website that provides both a search facility and normal navigation links.

## Introduction

Imagine that you open a website because you need to find a particular piece of information. You may enter keywords into its search box, or you may browse through menus and follow links until you reach a useful page. After reaching a page, you still need to read it, check whether it contains the information you need, and record the result.

Although this sounds like a simple activity, it consists of several actions and decisions. In Human-Computer Interaction (HCI), **Task Analysis** helps us understand these actions and how users complete a task. One common task-analysis technique is **Hierarchical Task Analysis (HTA)**.

This worked example develops a high-level HTA for finding information on a website.

## 1\. What Is Task Analysis?

Task Analysis is the process of examining how people perform a task or job. It considers:

- **Actions:** What does the user do?
- **Objects:** What does the user interact with?
- **Knowledge:** What does the user need to know to perform the task?

For example, cleaning a house may involve taking out a vacuum cleaner, attaching the correct tool, cleaning rooms, emptying the dust bag when necessary, and putting the equipment away. The person performing the task also needs to know how to use the vacuum cleaner and its attachments.

Task Analysis helps designers understand the real activities users perform instead of focusing only on the interface itself.

## 2\. What Is Hierarchical Task Analysis (HTA)?

**Hierarchical Task Analysis (HTA)** is a task-decomposition technique. It breaks a high-level goal into smaller tasks and subtasks, arranging them in a hierarchy.

An HTA normally describes three things:

1. **The overall goal:** What is the user trying to achieve?
2. **The task hierarchy:** Which smaller tasks make up the overall goal?
3. **The plans:** In what order, and under what conditions, should the subtasks be performed?

The hierarchy explains *what* the user needs to do, while the plans explain *how and when* the tasks are carried out.

## 3\. Worked Exercise: Finding Information on a Website

### Scenario and assumptions

Assume that a website provides two ways to locate information:

- A **search facility**, where the user enters keywords and reviews the results.
- **Normal links**, where the user browses a page, selects a relevant link, and follows it.

The goal is to find the required information, read the relevant page, and make a note of the information once it has been found.

### 3.1 Task hierarchy

The overall task is represented as task **0**. It is decomposed into five main tasks. Tasks 2 and 3 represent alternative ways of locating a relevant page: the user can search or browse.

```text
0. Find information on a website
   1. Decide how to look
   2. Search
      2.1 Type keywords
      2.2 Submit the search
      2.3 Scan the results
   3. Follow links
      3.1 Scan the page
      3.2 Choose a link
      3.3 Follow the link
   4. Read the page
   5. Note the information
```

**Figure 1. Hierarchical task structure for finding information on a website.**

![](https://cdn.hashnode.com/uploads/covers/69ba70b3c22d3eeb8a65156a/87465ddc-6c37-41d4-aded-6d8f33eb8788.svg align="center")

The hierarchy can be understood as follows:

- **Task 0 — Find information on a website:** This is the user's overall goal.
- **Task 1 — Decide how to look:** The user chooses whether to use the search facility or browse through links.
- **Task 2 — Search:** The user enters keywords, submits the query, and scans the results.
- **Task 3 — Follow links:** The user scans the current page, chooses a relevant link, and follows it.
- **Task 4 — Read the page:** The user reads the page that appears relevant and checks its content.
- **Task 5 — Note the information:** Once the required information is found, the user records or saves it.

Tasks 2 and 3 are not necessarily performed one after the other. They are alternative routes. The user normally chooses one route for an attempt and may switch routes if it does not lead to the required information.

## 4\. HTA Plans

In HTA, a plan describes the order in which tasks are performed and explains choices, conditions, and repetition. The plans for this example are given below.

### Plan 0: Overall plan

1. Perform task 1: decide how to look.
2. If the user chooses the search facility, perform task 2. Otherwise, perform task 3 by following links.
3. After locating a likely page, perform task 4 and read it.
4. If the required information is found, perform task 5 and note the information.
5. If the information is not found, return to task 1 and choose another approach or try again.

### Plan 2: Search plan

Perform the search subtasks in this order:

`2.1 → 2.2 → 2.3`

The user types keywords, submits the search, and scans the returned results.

### Plan 3: Browse plan

Perform the browsing subtasks in this order:

`3.1 → 3.2 → 3.3`

The user scans the current page, chooses a relevant link, and follows it. Repeat this sequence until a likely page is reached.

## 5\. Process Flow of the Task

The process-flow diagram below shows how the user moves through the task. It makes the choice between searching and browsing visible and also shows what happens when the information is not found.

**Figure 2. Process flow for finding information on a website.**

![](https://cdn.hashnode.com/uploads/covers/69ba70b3c22d3eeb8a65156a/b0ee8545-e32c-45b5-ab0c-9835a4dd2f1e.svg align="center")

The process begins when the user needs some information. The user decides how to look and selects one of two routes:

- **Search:** Enter keywords, submit the query, and scan the results.
- **Browse:** Scan the page, choose a relevant link, and follow it.

Both routes lead to reading a likely page. The user then checks whether the required information is present. If it is found, the user notes or saves it and the task ends. If it is not found, the user can refine the keywords, choose another link, or switch to the other method. The process then returns to the decision step.

## 6\. Why This HTA Is Useful in HCI

This analysis helps an interface designer understand the user's goals and the steps required to achieve them. It also highlights design requirements that might otherwise be overlooked:

- The search facility should be easy to locate and use.
- Search results should be understandable and relevant to the user's keywords.
- Navigation links should make it clear where they lead.
- Users should be able to return to earlier pages or try another route without losing their progress.
- Important information should be easy to identify and record.

By identifying these actions and decisions, HTA can help designers evaluate whether a website supports users in completing their tasks efficiently.

## 7\. Conclusion

Hierarchical Task Analysis provides a structured way to understand how users complete complex activities. In this example, the goal of finding information on a website is divided into smaller tasks: deciding how to look, searching or following links, reading the page, and noting the information.

The hierarchy shows the tasks and subtasks, while the plans explain their order, the choice between alternative methods, and the repetition required when the information is not found. This makes HTA a useful technique in HCI for understanding user behavior and designing interfaces that better support real tasks.

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