Comparison
Sierra vs Talkdesk
Compare documented workflows and implementation requirements using attributed public sources. Facts last checked , the earlier of the two records. Machine-readable record.
Start with your setup
These are documented product differences and requirements. A feature list or a single customer report does not establish which agent will perform better for your team.
Deployment model
Sierra
Sierra documents configuration through Agent Studio and custom integrations for proprietary systems. Deployment work includes defining journeys and connecting the systems those journeys use.Vendor-reported
- Source
- Agent Studio (Sierra)
- Checked
- History
- First published
- Correct this
- Request a correction with a public source. Claim ID
sierra-deployment
Talkdesk
Talkdesk describes itself as a cloud-based contact centre software platform, with Autopilot delivered as part of that hosted platform rather than as self-hosted software.Vendor-reported
- Source
- Talkdesk — Homepage
- Checked
- History
- First published
- Correct this
- Request a correction with a public source. Claim ID
talkdesk-cmp-deployment
Actions in backend systems
Sierra
The SDK lists subscription updates and warranty submissions as examples of actions through connected systems. Required permissions and workflow configuration depend on the implementation.Vendor-reported
- Source
- Agent SDK (Sierra)
- Checked
- History
- First published
- Correct this
- Request a correction with a public source. Claim ID
sierra-actions
Talkdesk
Talkdesk says its AI agents invoke external tools and services through a Multi-Context Protocol (MCP), and trade coverage reports integrations with core banking processors and e-commerce systems for actions such as fund transfers, card management and address changes.Vendor-reported
- Source
- Talkdesk AI Agents / Multi-Agent Orchestration
- Checked
- History
- First published
- Correct this
- Request a correction with a public source. Claim ID
talkdesk-cmp-actions
Human handoff
Sierra
The SDK documents routing to a team member with an automatic conversation summary.Vendor-reported
- Source
- Agent SDK (Sierra)
- Checked
- History
- First published
- Correct this
- Request a correction with a public source. Claim ID
sierra-handoff
Talkdesk
Talkdesk states Autopilot redirects customers to a human agent when it detects a complex case requiring human expertise, and works with Talkdesk Navigator for dynamic routing.Vendor-reported
- Source
- Talkdesk Autopilot — Self-Service Experience
- Checked
- History
- First published
- Correct this
- Request a correction with a public source. Claim ID
talkdesk-cmp-handoff
Side by side
Product attributes first, then what the sources establish for each customer workflow, then the industries they place each agent in. Open any claim to see its source, the date it was checked, and how to request a correction. Two agents are rarely documented to the same depth, so read a difference between the two columns as a difference in the public record before reading it as a difference in the products.
What this agent was judged by
No independent source has been found for any fit area, so every state here rests on vendor material or nothing.States rest on 0 independent sources. This is not the same yardstick for every agent, and that asymmetry is a known limitation.
What this agent was judged by
The independent evidence behind these states comes mainly from analysts and trade press.States rest on 1 independent source across analysts and trade press. This is not the same yardstick for every agent, and that asymmetry is a known limitation.
| Attribute | Sierra | Talkdesk |
|---|---|---|
| Review basis | Source-based review | Source-based review |
| Deployment model | Sierra documents configuration through Agent Studio and custom integrations for proprietary systems. Deployment work includes defining journeys and connecting the systems those journeys use.Vendor-reported
| Talkdesk describes itself as a cloud-based contact centre software platform, with Autopilot delivered as part of that hosted platform rather than as self-hosted software.Vendor-reported
|
| Channels | Vendor-listed channels include phone, website and app chat, WhatsApp, Apple Business Chat, SMS and email. Live Assist supports staff, and Sierra also documents publishing selected agent journeys to ChatGPT.Vendor-reported
| Talkdesk says its AI agents connect interactions across voice, digital, email and web, and describes Autopilot as resolving requests across voice and digital channels.Vendor-reported
|
| Languages | The current Channels page describes voice models tuned for 60+ locales. A locale is not the same as a language; verify the exact language, accent and channel required for your deployment.Vendor-reported
| Talkdesk states its AI agents support more than 59 languages so customers can interact in their preferred language.Vendor-reported
|
| Help desk and CRM integrations | Agent Studio lists 40+ prebuilt integrations for knowledge, systems of record and contact centers, but this page does not identify the help-desk connectors. Confirm your help desk and required handoff behavior with Sierra.Vendor-reported
| Talkdesk Embedded places Talkdesk tooling inside Salesforce, ServiceNow, Dynamics, Pega, Oracle and Zendesk, though the reported scope covers Workspace, Conversations and the agent-assist Copilot rather than Autopilot AI agents.Independent report
|
| Knowledge sources | The SDK documents ingestion of company FAQs, policies and documentation into its knowledge engine.Vendor-reported
| Talkdesk states Autopilot draws on Talkdesk Knowledge Management to search, review and extract the correct information, with the Talkdesk Data Cloud aggregating interaction data across systems of record, channels and knowledge sources.Vendor-reported
|
| Actions in backend systems | The SDK lists subscription updates and warranty submissions as examples of actions through connected systems. Required permissions and workflow configuration depend on the implementation.Vendor-reported
| Talkdesk says its AI agents invoke external tools and services through a Multi-Context Protocol (MCP), and trade coverage reports integrations with core banking processors and e-commerce systems for actions such as fund transfers, card management and address changes.Vendor-reported
|
| Human handoff | The SDK documents routing to a team member with an automatic conversation summary.Vendor-reported
| Talkdesk states Autopilot redirects customers to a human agent when it detects a complex case requiring human expertise, and works with Talkdesk Navigator for dynamic routing.Vendor-reported
|
| Target customer size | Sierra’s public customer examples include AOL, Minted and Ramp. These show deployments in established businesses; they do not define a minimum viable team size.Vendor-reported
| Procurement data from Vendr puts the median Talkdesk contract at $88,536 per year across 53 analysed deals, ranging from $16,566 to $768,775, and segments buyers into small teams of 10-25 agents, mid-market of 25-100 agents and enterprise of 100+ agents; the figures cover Talkdesk contracts overall rather than the AI agent alone, with AI capabilities reported to add $15-$30+ per agent per month.Independent report
|
| Vendor-reported performance claims | Sierra reports 90% case resolution at Ramp. This is a vendor-published customer result with no common benchmark population supplied here; it should not be compared directly with another vendor’s deflection or resolution figure.Vendor-reported
| Talkdesk publishes customer-attributed figures including a 60% containment rate at Quadient versus 33% previously, a 40% containment rate at UNFCU within the first week, an 89% improved service level at Michaels and a 5.3% abandonment-rate reduction at BankUnited.Vendor-reported
|
| Workflow evidenceBilling Illustrative scenario I was charged twice for the same order. Can you refund the extra payment? What to verify: Verify identity, inspect payment records, apply the refund policy, and confirm the payment-system result. If no authorized refund action is connected, hand off with the evidence. | Vendor-documented Illustrative evaluation: ask why a subscription charge increased, then request a card update. Verify identity checks, the source of the billing explanation and the permitted update path. 1 cited claim for billing on SierraSierra’s AOL case study describes explanations of outstanding balances, billing history and payment-method updates. The example is AOL’s configured agent, not a guarantee that every Sierra deployment includes billing access.Vendor-reported
| Vendor-documented No third-party account of billing-query handling in practice was found. 1 cited claim for billing on TalkdeskTalkdesk lists billing among the common customer queries Autopilot is designed to resolve.Vendor-reported
|
| Workflow evidenceOrders Illustrative scenario My order has not arrived. Where is it? What to verify: Retrieve the correct order and current carrier status. Distinguish a real tracking update from an estimate; do not invent a delivery date. | Vendor-documented Illustrative evaluation: use a split shipment with one delayed item. Require the agent to distinguish production status from carrier status and avoid promising a delivery date that the connected system does not provide. 1 cited claim for orders on SierraSierra’s Minted case study describes order updates across design approval, printing and shipping, plus priority-shipping changes for delayed orders. This supports an order-management use case in that deployment.Vendor-reported
| External report Both independent sources describe capability at launch announcements rather than measured production outcomes. 3 cited claims for orders on TalkdeskTalkdesk states Autopilot handles common customer queries such as orders, returns and billing across voice and digital channels.Vendor-reported
Trade coverage of Talkdesk AI Agents for Retail reports the agents handle customer authentication, real-time order updates and address modifications, integrating with existing commerce platforms and APIs.Independent report
Coverage of the Autopilot launch lists retail actions including order status inquiries, delivery scheduling, shipment tracking and address changes.Independent report
|
| Workflow evidenceReturns Illustrative scenario I bought this 12 days ago and opened the box. Can I return it? What to verify: Check the actual return window, product exclusions, and order record. A policy answer and an executed return are different capabilities. | Vendor-documented Illustrative evaluation: request an exchange for an item outside the normal return window. Check the configured exception policy, approval requirement and final state in the order system. 1 cited claim for returns on SierraSierra’s retail page lists refund requests and exchanges among supported workflows. It does not specify a universal return-policy configuration or prove that a particular refund reaches the payment processor.Vendor-reported
| Vendor-documented No third-party account of returns handling in practice was found. 1 cited claim for returns on TalkdeskTalkdesk lists returns among the common customer queries Autopilot is designed to resolve.Vendor-reported
|
| Workflow evidenceProduct questions Illustrative scenario Does this adapter work with my exact laptop model? What to verify: Use a current, approved compatibility source. Ask for the model when missing and distinguish documented compatibility from an assumption. | Vendor-documented Illustrative evaluation: ask whether an accessory works with an older product model. Supply an approved compatibility source and check that missing information leads to clarification rather than an invented answer. 1 cited claim for product questions on SierraSierra describes grounding answers in company knowledge, policies and brand guidance. That provides a route to product answers based on supplied content; it does not establish accuracy for a buyer’s catalog.Vendor-reported
| Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Workflow evidenceAccount issues Illustrative scenario I lost access to my email. Change the address on my account. What to verify: Follow the approved identity-recovery process before accessing or changing account data. Escalate when identity cannot be verified. | Vendor-documented Illustrative evaluation: an authenticated cardholder requests a replacement card and address change. Check permissions, address confirmation and the resulting card state before considering the journey complete. 1 cited claim for account issues on SierraSierra’s Ramp case study describes card locking and replacement, address validation and transaction explanations. These are account actions in Ramp’s configured implementation; password recovery and other account workflows require their own evidence.Vendor-reported
| External report Described as vertical capability at launch; no measured outcome data located, and no equivalent vendor doc page was fetched for this area. 1 cited claim for account issues on TalkdeskTrade coverage reports Autopilot's banking configuration covers account balance access, transaction history retrieval, fund transfers and card management, integrating with core banking processors.Independent report
|
| Workflow evidenceComplaints Illustrative scenario I have contacted you three times and the problem is still unresolved. What to verify: Recognize the repeat complaint, retain relevant history, and route it to the right team. Do not promise compensation outside the policy. | Vendor-documented Illustrative evaluation: a customer repeats a cancellation request after rejecting a retention offer. Check that the configured flow respects the refusal and provides the agreed cancellation or human-escalation path. 1 cited claim for complaints on SierraSierra says its agents can recognize frustration and adapt their responses. This is a vendor claim about conversational behavior, not a measured result for complaint resolution or customer satisfaction.Vendor-reported
| Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Workflow evidenceHuman handoff Illustrative scenario Please connect me to a person who can approve this exception. What to verify: Transfer to an available team with the conversation and relevant records. Outside working hours, explain the actual follow-up path rather than promise immediate contact. | Vendor-documented Illustrative evaluation: request a person during a failed account update. Check queue routing, transcript and summary delivery, plus what the customer sees when the team is offline. 1 cited claim for human handoff on SierraSierra’s SDK page documents routing an escalated conversation to a team member with a generated summary. It does not establish how quickly a human answers in a particular contact center.Vendor-reported
| External report Talkdesk states Autopilot seamlessly redirects customers to a human agent when it detects a complex case requiring human expertise. 2 cited claims for human handoff on TalkdeskTalkdesk states Autopilot seamlessly redirects customers to a human agent when it detects a complex case requiring human expertise.Vendor-reported
Trade coverage of Talkdesk AI Agents for Retail reports the agents support routing to in-store specialists, escalating from AI to a human when necessary.Independent report
|
| Workflow evidenceSmall businesses Illustrative scenario A two-person support team wants to launch without a dedicated engineer. What to verify: Validate setup effort, existing help-desk support, required integrations, and ongoing maintenance. A small customer's story alone does not establish suitability for every small business. | Not established Business size alone does not establish suitability. Illustrative buying scenario: a small team needs one FAQ channel; ask for the implementation work and ongoing maintenance required for that scope before deciding whether the platform is proportionate. No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Workflow evidenceMid-market Illustrative scenario A growing support team needs separate queues and connected order and account systems. What to verify: Validate routing, permissions, integration ownership, and handling of each team's policies in the intended configuration. | Not established The reviewed sources do not establish a universal mid-market fit. Illustrative buying scenario: a growing retailer needs order support across two brands; evaluate connector coverage, ownership of policy updates and support capacity for that deployment. No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Workflow evidenceEnterprise Illustrative scenario A multi-brand support organization needs controlled access across regional teams. What to verify: Validate data boundaries, audit records, escalation ownership, and the specific deployment requirements. A vendor's enterprise positioning is not proof of these controls. | Vendor-documented Illustrative buying scenario: multiple business units need separate permissions and policies. Request a demonstration using those boundaries and review the operational and security requirements of the proposed deployment. 1 cited claim for enterprise on SierraSierra publishes customer stories for AOL, Minted and Ramp, including connected service workflows. These are vendor-published deployment examples, not proof that every enterprise requirement is met.Vendor-reported
| Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Industry evidenceRetail and e-commerce | Vendor-documented Sierra's retail and consumer goods page lists refunds and exchanges among supported workflows. Vendor documentation only; no retail deployment is independently reported. 1 cited claim for retail and e-commerce on SierraSierra’s retail page lists refund requests and exchanges among supported workflows. It does not specify a universal return-policy configuration or prove that a particular refund reaches the payment processor.Vendor-reported
| External report Trade coverage of two launches describes retail agents handling authentication, order updates, address changes and routing to in-store specialists. This is coverage of what was announced, not of how the released product performed. 3 cited claims for retail and e-commerce on TalkdeskTrade coverage of Talkdesk AI Agents for Retail reports the agents handle customer authentication, real-time order updates and address modifications, integrating with existing commerce platforms and APIs.Independent report
Trade coverage of the Autopilot launch reports it ships pre-trained on banking, credit-union and retail scenarios with prebuilt flows, including resolving requests such as 'Cancel an Item in My Order' without model training or flow-building.Independent report
Trade coverage of Talkdesk AI Agents for Retail reports the agents support routing to in-store specialists, escalating from AI to a human when necessary.Independent report
|
| Industry evidenceFinancial services | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | External report Trade coverage reports banking and credit-union flows shipping pre-trained, and Talkdesk publishes containment figures attributed to a credit union and a bank. The named outcomes are the vendor's own. 3 cited claims for financial services on TalkdeskTalkdesk publishes customer-attributed figures including a 60% containment rate at Quadient versus 33% previously, a 40% containment rate at UNFCU within the first week, an 89% improved service level at Michaels and a 5.3% abandonment-rate reduction at BankUnited.Vendor-reported
Trade coverage of the Autopilot launch reports it ships pre-trained on banking, credit-union and retail scenarios with prebuilt flows, including resolving requests such as 'Cancel an Item in My Order' without model training or flow-building.Independent report
Trade coverage reports Autopilot's banking configuration covers account balance access, transaction history retrieval, fund transfers and card management, integrating with core banking processors.Independent report
|
| Industry evidenceTelecommunications | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Industry evidenceTravel and hospitality | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Industry evidenceHealthcare | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Industry evidencePublic sector and education | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Industry evidenceLogistics and delivery | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Channels | ||
| Web and in-app chat | Vendor-documented Vendor-listed channels include phone, website and app chat, WhatsApp, Apple Business Chat, SMS and email. Live Assist supports staff, and Sierra also documents publishing selected agent journeys to ChatGPT. 1 cited claim for web and in-app chat on SierraVendor-listed channels include phone, website and app chat, WhatsApp, Apple Business Chat, SMS and email. Live Assist supports staff, and Sierra also documents publishing selected agent journeys to ChatGPT.Vendor-reported
| Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Vendor-documented Vendor-listed channels include phone, website and app chat, WhatsApp, Apple Business Chat, SMS and email. Live Assist supports staff, and Sierra also documents publishing selected agent journeys to ChatGPT. 1 cited claim for email on SierraVendor-listed channels include phone, website and app chat, WhatsApp, Apple Business Chat, SMS and email. Live Assist supports staff, and Sierra also documents publishing selected agent journeys to ChatGPT.Vendor-reported
| Vendor-documented Talkdesk says its AI agents connect interactions across voice, digital, email and web, and describes Autopilot as resolving requests across voice and digital channels. 1 cited claim for email on TalkdeskTalkdesk says its AI agents connect interactions across voice, digital, email and web, and describes Autopilot as resolving requests across voice and digital channels.Vendor-reported
| |
| Voice and phone | Vendor-documented Vendor-listed channels include phone, website and app chat, WhatsApp, Apple Business Chat, SMS and email. Live Assist supports staff, and Sierra also documents publishing selected agent journeys to ChatGPT. 1 cited claim for voice and phone on SierraVendor-listed channels include phone, website and app chat, WhatsApp, Apple Business Chat, SMS and email. Live Assist supports staff, and Sierra also documents publishing selected agent journeys to ChatGPT.Vendor-reported
| Vendor-documented Talkdesk says its AI agents connect interactions across voice, digital, email and web, and describes Autopilot as resolving requests across voice and digital channels. 1 cited claim for voice and phone on TalkdeskTalkdesk says its AI agents connect interactions across voice, digital, email and web, and describes Autopilot as resolving requests across voice and digital channels.Vendor-reported
|
| SMS | Vendor-documented Vendor-listed channels include phone, website and app chat, WhatsApp, Apple Business Chat, SMS and email. Live Assist supports staff, and Sierra also documents publishing selected agent journeys to ChatGPT. 1 cited claim for sms on SierraVendor-listed channels include phone, website and app chat, WhatsApp, Apple Business Chat, SMS and email. Live Assist supports staff, and Sierra also documents publishing selected agent journeys to ChatGPT.Vendor-reported
| Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Vendor-documented Vendor-listed channels include phone, website and app chat, WhatsApp, Apple Business Chat, SMS and email. Live Assist supports staff, and Sierra also documents publishing selected agent journeys to ChatGPT. 1 cited claim for whatsapp on SierraVendor-listed channels include phone, website and app chat, WhatsApp, Apple Business Chat, SMS and email. Live Assist supports staff, and Sierra also documents publishing selected agent journeys to ChatGPT.Vendor-reported
| Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | |
| Social messaging | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Help desks | ||
| Zendesk | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Salesforce | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| ServiceNow | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Freshdesk | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Intercom | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| HubSpot | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Kustomer | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Gorgias | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Gladly | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Help Scout | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Front | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
| Microsoft Dynamics 365 | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. | Not established No supporting source is recorded here. Validate it with the vendor; absence of evidence does not establish a missing capability. |
Change history
Open the changelogEvery change to this record is in the public changelog, with what it changed and why.
· Structure
Channels and help desks become evidence rows, and records gain bylines
Sierra: 5 evidence states moved
- Channel · Web and in-app chatNot established→Vendor-documented
- Channel · EmailNot established→Vendor-documented
- Channel · Voice and phoneNot established→Vendor-documented
- Channel · SMSNot established→Vendor-documented
- Channel · WhatsAppNot established→Vendor-documented
Talkdesk: 2 evidence states moved
- Channel · EmailNot established→Vendor-documented
- Channel · Voice and phoneNot established→Vendor-documented
· Catalog
Launch: 22 AI customer service agents and 532 claims, every one sourced and dated
Sierra: Added to the catalog with 23 claims and 9 rows with evidence.
Talkdesk: Added to the catalog with 26 claims and 7 rows with evidence.
Recorded before launch
Notes the profile carried when it went live, from research before launch.
Sierra: Added editorial product positioning with its scope, rationale, and vendor source. Source
Sierra: Rechecked public sources; replaced broad fit verdict evidence with specific deployment examples and evaluation conditions. Removed unverified attribution, relayed marketing treated as independent confirmation, and business-size exclusions without evidence.