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250 Respondents, 250 Quality Verbatims: KLA Puts AI Interviews to the Test

How KLA ran WhatsApp AI interviews for a major South African bank's board presentation, set them beside human qualitative interviews, and couldn't tell them apart.

KLA x Yazi case study card: 250 Respondents, 250 Quality Verbatims, KLA Puts AI Interviews to the Test
Yazi case study · Market research

How KLA ran WhatsApp AI interviews for a major South African bank's board presentation, set them beside human qualitative interviews, and couldn't tell them apart.

250
AI interviews, each with a usable verbatim
1 in 3
Invited customers started the interview, in two batches a few days into fieldwork
3
Research strands compared side by side
Client
KLA
Industry
Market research
Location
South Africa
Timeline
Aug to Sep 2025

In short

KLA, a South African research agency, ran 250 WhatsApp AI interviews on Yazi for one of the country's major banks in August and September 2025, beside 50 human qualitative interviews and about 10,000 coded customer comments. The themes in the AI interviews matched the human ones, and every AI interview gave KLA a usable verbatim for the bank's board presentation.

  • 250 AI interviews, each with a usable verbatim
  • Themes matched the 50 human qualitative interviews
  • About 1 in 3 invited customers started the interview
01The brief

A bank's board presentation, due within weeks

KLA is a South African research agency and one of Yazi's longest-standing clients. In August 2025 one of the country's major banks asked KLA to show how its customers felt about their banking experience, in time for a presentation to the bank's board.

KLA designed three strands: about 10,000 existing customer comments coded for themes, 50 qualitative interviews, and a new strand of AI interviews on WhatsApp with the bank's customers, run on Yazi. The target for the WhatsApp strand was 150 to 200 interviews.

02The challenge

Depth, speed and data security, with a board waiting

A board deadline

The bank was presenting to its board, so fieldwork couldn't slip.

Sensitive customer data

The bank's customer list couldn't be passed around by email or FTP.

Doubts about depth

The fear with WhatsApp interviews is short, SMS-style answers.

Proving validity

AI interview findings had to hold up next to human interviews on the same topics.

03The approach

AI interviews on WhatsApp, run beside the human ones

KLA's lead consultant uploaded the bank's customer list straight into Yazi, so the data never travelled by email. Yazi set up the WhatsApp invitation and the AI Interviewer, which asked each customer about their experience and followed up on what they said, by text or voice. Invitations went out in batches, and KLA watched interviews start within minutes of the first send.

Customers responded warmly. Several replied to thank the bank for selecting them.

Three strands, one question

Did the AI interviews tell the same story as the human ones?

1
Upload. KLA loads the bank's customer list directly into Yazi.
2
Invite. Customers receive a WhatsApp invitation, in batches.
3
Interview. The AI Interviewer asks and follows up, by text or voice.
4
Compare. KLA sets the AI transcripts beside its human interviews and coded comments.
AI interviewsVoice notesDirect list uploadTriangulation

Illustrative screen showing how the conversation worked. Not a real participant. One customer sent a single voice note four and a half minutes long.

04Results

250 interviews, and a usable verbatim in every one

Three strands, three kinds of evidence

How many responses each strand produced, and how much each response said

Depth at scale 10 100 1,000 10,000 Number of responses (log scale) Full conversation Short comment ~10,000 existing comments, coded 50 human qualitative interviews 250 WhatsApp AI interviews
KLA study for a South African bank, Aug to Sep 2025

The WhatsApp strand reached 250 completed AI interviews, drawing on the bank's customers and KLA's own panel. KLA's lead consultant found "one or two nuggets per person", with answers far longer than the SMS-style replies he had feared. One customer sent a single voice note four and a half minutes long.

About 1 in 3 invited customers started the interview

Two batches sent a few days into fieldwork, as read out at the time

Batch A 162 50 Batch B 147 45 Invited Started the interview
KLA study for a South African bank, Sep 2025 · Yazi platform figures, indicative

Side by side with the human interviews

KLA then set the AI transcripts next to the human interviews on the same topics. The themes matched, which gave the team confidence in the method's validity. KLA shared the transcripts with the bank's senior team, and the bank was happy with the result.

“The fear with a WhatsApp interview is that you'll get short, SMS-style answers, but people expressed themselves well.”

Senior consultant, KLA

“Side by side, what was being said was quite similar. So in terms of validity, it's quite powerful.”

Senior consultant, KLA
05The relationship

From one diary study to agency-wide training

How the work grew

Jul to Aug 2024
First study
A WhatsApp diary for a wine brand, run before focus groups.
2024 to 2025
Repeat projects
More WhatsApp diaries and studies, and a proposal won with a WhatsApp diary in it.
Aug to Sep 2025
Bank AI interviews
250 AI interviews beside human qual, for a board presentation.
May 2026
Training request
More KLA projects use Yazi, so teams ask for training.
Jun 2026
Agency-wide session
Around 40 KLA staff join a formal introduction to Yazi.
Jul 2026
Into proposals
KLA starts using Yazi pricing in its proposals.
Sep to Oct 2026
Four-week daily diary
A daily WhatsApp spend diary with low-income participants, hosted fully on Yazi.

“I'd like them to start thinking about it more, because it gives us a bit of an edge in how we do research.”

Cindy de Lima, KLA

“I want our proposal team to be there, because I want them to be throwing it into their proposals.”

Cindy de Lima, KLA
06Before and after

Human depth interviews and AI interviews, side by side

Human depth interviewsAI interviews on WhatsApp
Sample50 interviews250 interviews
Customer dataLists shared by email or FTPUploaded straight into the platform
Answer depthDepth from a skilled interviewerMatching themes and verbatims, by text or voice
SchedulingBooked in working hoursCustomers reply when it suits them
AnalysisRecordings to transcribeTranscripts ready as interviews finish
07Impact

A validity question answered on a live project

For KLA

Evidence from a live client project that AI interviews hold up against human qualitative work. KLA has since trained its teams on Yazi and started building it into its proposals.

For the bank

Customer voices from 250 conversations, ready for the board, alongside the coded comments and human interviews.

“

From the 250 people that responded, I could get out 250 quality verbatims. If I put them side by side and asked you which one is qual and which one is AI, you wouldn't be able to tell the difference.

Senior consultant and statistician, KLA, at the time of the study
08Conclusion

The validity question got a practical answer

Agencies asking whether AI interviews count as real qual rarely get to test it on a live project. KLA did, with a board deadline and a bank's customers. The AI interviews gave it the reach of a survey with themes that matched its human interviews, and KLA has kept using them since.

09FAQ

Frequently asked questions

Are AI interviews as good as human qualitative interviews?

In KLA's study for a South African bank, the themes in 250 AI interviews matched 50 human interviews on the same topics. KLA's senior consultant said that side by side, you wouldn't be able to tell which was which. KLA used the AI interviews beside its human interviews, not instead of them.

How long are answers in WhatsApp AI interviews?

Longer than many expect. KLA's lead consultant found one or two nuggets per person rather than short, SMS-style replies, and one customer sent a single voice note four and a half minutes long.

How was the bank's customer data kept secure?

KLA uploaded the bank's customer list straight into Yazi, so the data never travelled by email or FTP.

Want to test AI interviews against your own qual?

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