Interaksi Manusia dan Komputer
Evaluation Technique
Prodi Rekayasa Perangkat Lunak
Universitas Pendidikan Indonesia - Kampus Cibiru
Dr. Asep Wahyudin, S.Kom., MT.
Asyifa Imanda Septiana, S.Pd., M.Eng.
"G ood design is actually a lot harder to notice than poor design, in part because good designs fit our needs so well that the design is invisible."
– Donald Norman.
Definisi Evaluation
• tests usability and functionality of system
• occurs in laboratory, field and/or in collaboration with users
• evaluates both design and implementation
• should be considered at all stages in the design life cycle
Evaluasi digunakan untuk melihat apakah hasil rancangan dengan proses uji coba system yang telah dibuat sesuai dengan permintaan
pengguna (user)
Goal
• assess extent of system functionality
• assess effect of interface on user
• identify specific problems
Evaluating Designs
• Cognitive Walkthrough
• Heuristic Evaluation
• Review-based evaluation
Proposed by Polson et al.
• evaluates design on how well it supports user in learning task
• usually performed by expert in cognitive psychology
• expert ‘walks though’ design to identify potential problems using psychological principles
• forms used to guide analysis
Psikologi kognitif adalah cabang ilmu psikologi yang mempelajari proses mental seperti
"perhatian, penggunaan bahasa, daya ingat, persepsi, pemecahan masalah, kreativitas, dan pola pikir"
Evaluating Designs
• Cognitive Walkthrough
• Heuristic Evaluation
• Review-based evaluation
• For each task walkthrough considers
o what impact will interaction have on user?
o what cognitive processes are required?
o what learning problems may occur?
• Analysis focuses on goals and knowledge:
does the design lead the user to generate the correct goals?
Harus mempunyai informasi yang dibutuhkan : o Deskripsi dari interface
o Deskripsi dari tugas (task)
o Langkah tugas/task yang benar Dengan Informasi ini Evaluator dapat : o Memilih Tugas
o Mendiskrpsikan Tujuan dari user o Melakukan kegiatan yang tepat
o Menaganalisa proses keputusan untuk setiap kegiatan
Evaluating Designs
• Cognitive Walkthrough
• Heuristic Evaluation
• Review-based evaluation
Proposed by Nielsen and Molic.
• usability criteria (heuristics) are identified
• design examined by experts to see if these are violated
• Example heuristics
o system behaviour is predictable o system behaviour is consistent o feedback is provided
• Heuristic evaluation `debugs' design.
• Prinsip ini dikemukakan oleh Jacob Nielsen (1995a) dan dikenal dengan istilah 10 Usability Heuristic for User Interface Design.
• Nielsen juga mengemukakan Severity Rating for Usability Problems sebagai skala penilaian tentang keparahan untuk masalah usability dari evaluasi heuristiknya. Yaitu, berupa peringat dari 0 sampai 4.
0 = tidak setuju, tidak menjadi masalah.
1 = tidak perlu diperbaiki, kecuali tersedia waktu tambahan untuk project.
2 = permasalahan cukup serius, prioritas rendah.
3 = permasalahan serius, prioritas tinggi.
4 = penting untuk melakukan perbaikan sebelum product direlease.
• Heuristic, atau usability guidelines, adalah aturan yang menguraikan prinsip- prinsip user interface yang efektif.
• Heuristic Evaluation (HE) adalah prinsip yang digunakan untuk mengevaluasi interaksi dan antarmuka sebuah sistem atau aplikasi
Evaluating Designs
• Cognitive Walkthrough
• Heuristic Evaluation
• Review-based evaluation
Step 1: Definisikan Batasan Masalah
Lakukan evaluasi sesuai kebutuhan. Apakah produk ini membutuhkan analisa menyeluruh? Jika waktu yang tersedia cukup singkat, evaluasi harus dibataskan pada beberapa masalah kegunaan (contohnya registrasi, checkout, dsb.).
Step 2: Kenali Kepentingan User
Tujuan utama dari proses ini adalah membuat produk yang ramah digunakan oleh user. Kenali apa saja yang akan seorang user harapkan dari produk ini? Mengetahui kebutuhan bisa melakukan interview atau riset dengan user
Step 3: Tentukan Heuristics yang Digunakan
Jabarkan prinsip-prinsip desain yang akan menjadi tolak ukur bagi para evaluator. (salah satunya pakai prinsip heuristics yang ditentukan oleh Nielsen)
Step 4: Susun Tahapan Evaluasi
Bersama para evaluator, diskusikan bagaimana dan sejauh apa produk akan ditinjau. Masalah-masalah yang dilaporkan nantinya akan diukur dengan skala severity (keparahan)
Step 5: Ringkaskan dan Analisa Hasil
Akhir proses, evaluator menyerahkan hasil observasi secara individu. Lakuakn meeting team desain agar hasil dapat dianalisa secara bersama, kemudian bahas dan utarakan saran dan masukan yang membangun.
Heuristic Evaluation (HE) adalah prinsip yang digunakan untuk mengevaluasi interaksi dan antarmuka sebuah sistem atau aplikasi
Evaluating Designs
• Cognitive Walkthrough
• Heuristic Evaluation
• Review-based evaluation
The system should always keep users informed about what is going on, through appropriate feedback within reasonable time
https://www.nngroup.com/articles/visibility-system-status/
The system should speak the users' language, with words, phrases and concepts familiar to the user, rather than system-oriented
terms. Follow real-world conventions, making information appear in a natural and logical order.
https://www.nngroup.com/articles/match-system-real-world/
#1
#2
#3
Users often choose system functions by mistake and will need a clearly marked "emergency exit" to leave the unwanted state without having to go through an extended dialogue. Support undo and redo.
#4
https://www.nngroup.com/videos/usability-heuristic- user-control-freedom/
Users should not have to wonder whether different words, situations, or actions mean the same thing.
https://www.nngroup.com/videos/usability- heuristic-consistency-standards/
Ten Usability Heuristic
#5
Even better than good error messages is a careful design which prevents a problem from occurring in the first place. Either
eliminate error-prone conditions or check for them and present users with a confirmation option before they commit to the action.
https://www.nngroup.com/articles/slips/
#7
Minimize the user's memory load by making obj ects, actions, and options visible. The user should not have to remember information from one part of the dialogue to another. Instructions for use of the system should be visible or easily retrievable whenever appropriate.
https://www.nngroup.com/articles/recognition-and-recall/
Accelerators — unseen by the novice user — may often speed up the interaction for the expert user such that the system can cater to both inexperienced and experienced users.
Allow users to tailor frequent actions.
#6
https://www.nngroup.com/videos/flexibility-efficiency-use/
Ten Usability Heuristic
#8 Dialogues should not contain information which is irrelevant or rarely needed. Every extra unit of information in a
dialogue competes with the relevant units of information and diminishes their relative visibility.
Error messages should be
expressed in plain language (no codes), precisely indicate the problem, and constructively suggest a solution.
https://www.nngroup.com/videos/aesthetic-and-minimalist-design/
#9
https://www.nngroup.com/videos/usability-heuristic-recogniz e-errors/
Even though it is better if the system can be used without documentation, it may be necessary to provide help and documentation. Any such
information should be easy to search, focused on the user's task, list concrete steps to be carried out, and not be too large.
https://www.nngroup.com/videos/help-and- documentation/
#10 0
Ten Usability Heuristic
Feedback menu yang kurang jelas 2016
Penggunaan type face:
1. Tidak menjelaskan user sudah berpindah halaman menu
2. Tidak menunjukkan pengguna sedang berada pada menu apa karena background activated button tidak kentara
Evaluating Designs
• Cognitive Walkthrough
• Heuristic Evaluation
• Review-based evaluation
Saran perbaikan
1. Penambahan animasi pada teks menu
2. Penegasan dengan Bold, akan menjadi lebih jelas menunjukkan user sedang berada pada menu apa.
3. Penggunaan background activated button dibuat lebih gelap.
Skala severitas
2 = permasalahan cukup serius, prioritas rendah.
Evaluating Designs
• Cognitive Walkthrough
• Heuristic Evaluation
• Review-based evaluation
• Results from the literature used to support or refute parts of design.
• Care needed to ensure results are transferable to new design.
• Model-based evaluation
• Cognitive models used to filter design options e.g. GOMS prediction of user performance.
• Design rationale can also provide useful evaluation information
Evaluating Designs
• Cognitive Walkthrough
• Heuristic Evaluation
• Review-based evaluation
Contoh Goals
goal
edit dokumen, subgoal
insert word Operators
• Tekan tombol panah atas
• Pindahkan tangan ke mouse
• Ingat nama file
• Pastikan kursor ada di akhir baris Method
Pindahkan kursor ke lokasi yg diinginkan dgn serentetan penekanan tombol panah Selection Rules
Menghapus dengan backspace berkali-kali vs. memblok dan menekan tombol delete
GOMS Model
• Goals, Operators, Methods, and Selection Rules
• Model diusulkan oleh Card, Moran dan Newell (1980, 1983)
Evaluating Designs
• Cognitive Walkthrough
• Heuristic Evaluation
• Review-based evaluation
Goals
User formulates goals(edit document) and subgoals(insert word) Operators
• Elementary, motor or cognitive acts whose execution is necessary to change any aspect of the user’s mental state or to affect the task environment”
• (press key, move hand, recall filename, verify cursor position) Methods
Used to achieve the goals(moving cursor by repeated keystroking) Selection
• Among different methods to accomplish the goal
• Production rules to describe conditions and actions in interactive text editing
• Transition diagrams to model interactive systems
GOMS Model
• Goals, Operators, Methods, and Selection Rules
• Model diusulkan oleh Card, Moran dan Newell (1980, 1983)
Nuhun
Semoga bermanfaat
