CCPP Module 27, Section 3: Developing MTM, CCM, and Preventive-Care Service Lines
Module 27: Entrepreneurial Strategy and Private Practice Development

Section 3: Developing MTM, CCM, and Preventive-Care Service Lines

A practical guide to building profitable service lines around established, reimbursable CPT codes, including Medication Therapy Management (MTM) and Chronic Care Management (CCM).

SECTION 27.3

Developing MTM, CCM, and Preventive-Care Service Lines

From Cash-Pay to Covered Service: Building a Hybrid Practice with Reimbursable Revenue Streams.

27.3.1 The “Why”: Diversification is the Key to a Resilient Practice

In the previous sections, we focused on building the foundational business plan and pricing structure for a direct-to-consumer, cash-based consulting practice. This is an essential and often liberating model that allows you to define your value without the constraints of third-party payers. However, a practice built solely on cash-pay services, while viable, can be limited in its reach and susceptible to market fluctuations. To build a truly robust, scalable, and resilient practice, you must learn to diversify your revenue streams. This means strategically incorporating services that are recognized and reimbursed by payers like Medicare Part D plans and physician offices.

This section is your masterclass in building the “hybrid” practice model. We will pivot from the art of pricing your value in the open market to the science of delivering and documenting your value according to the specific rules of established medical billing codes. By mastering services like Medication Therapy Management (MTM) and Chronic Care Management (CCM), you accomplish several critical business objectives. First, you expand your market significantly by tapping into a vast pool of patients whose services are covered by their insurance. Second, you increase your credibility with other healthcare providers by demonstrating fluency in the language of CPT codes and medical billing. Third, you create more stable, predictable revenue streams that can complement your cash-based services, smoothing out the inevitable ebbs and flows of a purely project-based business.

The learning curve for medical billing can be steep, and the rules can seem arcane. But the effort is profoundly worthwhile. The services defined by these codes—comprehensive medication reviews, ongoing care coordination for chronic diseases—are the very definition of advanced pharmacy practice. They are what you were trained to do. Learning how to properly document and bill for them is not just a business skill; it is an act of professional actualization. It is the final step in aligning your clinical expertise with a sustainable business model that allows you to help more patients, more profoundly.

Pharmacist Analogy: Building a Compounding Practice

Imagine you are a pharmacist skilled in the art of compounding. Your initial business model is based on creating high-end, cash-pay custom formulations like bioidentical hormones or specialized dermatological creams. This is your cash-based service line. You have full control over your formulas and pricing, and you attract a niche clientele willing to pay for your unique expertise.

However, to grow your business, you recognize an opportunity. A local pediatric hospital needs a reliable source for “magic mouthwash” and custom liquid suspensions of medications that are not commercially available. A hospice agency needs patient-specific pain and nausea suppositories. These are not luxury items; they are medically necessary treatments. To serve these clients, you must learn the entirely new skill set of third-party billing. You need to learn how to process prescriptions through insurance, use the correct National Drug Codes (NDCs), and properly document your formulas for potential audits. The reimbursement rates are fixed and often lower than your cash prices, but the volume is much higher and more consistent.

  • MTM Services are like your standard, billable compounds. The “formula” (the requirements for a Comprehensive Medication Review) is well-defined by the payer (e.g., a Medicare Part D plan). You must follow the recipe precisely to get paid.
  • CCM Services are like providing a “compound of the month” to a physician’s office. It’s a recurring, predictable need. You create a system to deliver this service efficiently every month, and in return, you get a stable, recurring revenue stream.

By adding this billable compounding service to your cash-based practice, you haven’t abandoned your core expertise. You have diversified. You now have two distinct revenue streams serving different market needs, making your overall business far more stable and resilient. This is the exact model we will build for your clinical consulting practice.

27.3.2 Deep Dive: Medication Therapy Management (MTM)

MTM is one of the most well-known and established opportunities for pharmacist reimbursement. Mandated by the Medicare Prescription Drug, Improvement, and Modernization Act of 2003, all Medicare Part D plans are required to offer an MTM program to eligible beneficiaries. This creates a massive, built-in market for your services. While the term “MTM” is used broadly, for billing purposes, it refers to a specific set of services with defined requirements and CPT codes.

The Core Components of a Billable MTM Service

A complete MTM service, as defined by CMS and pharmacy benefit managers (PBMs), has several required components. Simply talking to a patient about their medications does not qualify. To be reimbursed, you must deliver and document the following:

  • Comprehensive Medication Review (CMR): This is the cornerstone of MTM. It is a systematic process of collecting patient-specific information, assessing medications for appropriateness, efficacy, safety, and adherence, and developing a plan to resolve any medication-related problems. This is typically required to be offered annually to eligible patients.
  • Targeted Medication Review (TMR): These are more focused, ongoing reviews performed at least quarterly to assess and address specific medication-related problems that have been identified.
  • Personal Medication List (PML): You must provide the patient with a complete, reconciled list of all their medications, including prescription, OTC, and supplements.
  • Medication Action Plan (MAP): A patient-centric document that outlines what the patient needs to do to manage their medications and achieve their health goals. It should be written in plain language and be actionable for the patient.
  • Intervention & Referral: You must communicate your findings and recommendations to the patient’s prescribers and, when necessary, refer the patient to other healthcare professionals. Meticulous documentation of these communications is essential.
The MTM CPT Codes You Must Know

The American Medical Association has established three CPT codes specifically for MTM services provided by pharmacists. These are the codes used for billing, whether you are working through a platform like OutcomesMTM or billing directly.

CPT Code Description Key Billing Requirements Typical Reimbursement Range
99605 Medication therapy management service(s) provided by a pharmacist, individual, face-to-face with a patient, with assessment and intervention if provided; initial 15 minutes, new patient.
  • Used for the first encounter with a new MTM patient.
  • Must be a face-to-face (or approved telehealth) encounter.
  • Requires a full CMR and all associated documentation (PML, MAP).
 $60 – $120
99606 …initial 15 minutes, established patient.
  • Used for subsequent annual CMRs for a patient you have seen before.
  • Essentially the same service as 99605, but for a returning patient.
 $50 – $100
99607 …each additional 15 minutes. (List separately in addition to code for primary service).
  • This is an “add-on” code.
  • Used for both new and established patients when the face-to-face encounter exceeds the initial 15 minutes.
  • Example: A 40-minute CMR for a new patient would be billed as: 99605 (for the first 15 mins) + 99607 x 1 (for the next 15 mins). The final 10 mins are not billable under a new unit. Meticulous time documentation is crucial.
 $20 – $40 per unit

How to Build an MTM Service Line: A Step-by-Step Tutorial

Let’s walk through the practical steps of establishing and running an MTM service.

Pharmacist’s Playbook: The MTM Workflow
  1. Step 1: Get Contracted. The vast majority of MTM cases are generated by large Part D plans and administered through third-party platforms. You must contract with these platforms to get access to eligible patients in your area.
    • Key Platforms: OutcomesMTM (a Cardinal Health company) and Mirixa (owned by the PBM industry).
    • The Process: You will need to complete their application process, which includes providing your NPI number, proof of licensure, and professional liability insurance. Once approved, you gain access to their online platform, which lists eligible patients and the cases available for completion.
    • Alternative: Direct Contracting. While less common for solo practitioners, you can approach local physician groups or self-funded employers to provide MTM services directly, bypassing the large platforms. This requires a much heavier lift in terms of marketing and legal agreements but can be more lucrative.
  2. Step 2: Identify and Schedule Patients. The platform will provide you with lists of eligible beneficiaries. Your job is to contact them and schedule the CMR.
    • The Script: “Hello, Mrs. Smith? My name is [Your Name], and I am a clinical pharmacist working with your Medicare prescription plan, [Plan Name]. Your plan offers a free, private consultation with a pharmacist each year to review your medications and ensure they are working well for you. This service is called Medication Therapy Management and is a covered benefit of your plan. Would you be open to scheduling a 30-45 minute appointment with me to go over your medications?”
  3. Step 3: Prepare for the CMR (The Pre-Work). This is critical for efficiency. Before the appointment, review the patient’s available prescription history from the MTM platform. Identify potential drug therapy problems (DTPs) in advance: therapeutic duplications, non-adherence, high-risk medications in the elderly (Beers List), doses that may need renal adjustment, etc. This allows you to walk into the appointment with a set of specific questions.
  4. Step 4: Conduct the CMR. This is the face-to-face encounter. Use a systematic process. A common method is to go through each medication one by one, asking:
    • “What do you take this medication for?” (Assesses understanding)
    • “How do you actually take it?” (Assesses adherence vs. prescribed sig)
    • “What problems or side effects have you noticed?” (Assesses tolerability/adverse effects)
    • “How do you know it’s working?” (Assesses efficacy)
    • Also, be sure to ask about all OTCs, vitamins, and herbal supplements.
  5. Step 5: Create the MAP and PML. At the end of the visit, provide the patient with their printed Medication Action Plan and Personal Medication List. The MAP should be simple and clear (e.g., “1. Talk to Dr. Jones about your dizziness. 2. Remember to take your cholesterol pill every night. 3. Call me if you have questions.”). The PML should be a clean, easy-to-read list of all medications.
  6. Step 6: Document and Bill. This is the final, crucial step. You must log into the MTM platform and document every single thing you did. This includes:
    • The drug therapy problems you identified.
    • The recommendations you made to the patient and/or prescriber.
    • The time spent in the face-to-face encounter (for billing 99607).
    • Confirmation that you provided the MAP and PML.
    • Fax or electronically send your detailed recommendations to the relevant prescribers.
    Once all documentation is complete, you submit the claim through the platform for payment.

27.3.3 Deep Dive: Chronic Care Management (CCM)

If MTM is an annual, episodic intervention, Chronic Care Management is a longitudinal, ongoing service. Introduced by CMS in 2015, CCM provides monthly reimbursement to physicians and other qualified healthcare professionals for the non-face-to-face time they spend managing care for patients with multiple chronic conditions. This created a monumental opportunity for pharmacists. While pharmacists cannot bill directly for CCM services (yet), they are perfectly positioned to provide these services “incident to” a physician, meaning under the physician’s supervision and billing number. For many consulting pharmacists, running a CCM program for a local primary care office is their most stable and lucrative service line.

The Core Components of a Billable CCM Service

To bill for CCM, a practice must meet a strict set of requirements defined by CMS. As the pharmacist running the program, you are responsible for ensuring every single one of these elements is fulfilled and documented each month for each enrolled patient.

  • Eligible Patient: The patient must have two or more chronic conditions expected to last at least 12 months or until the death of the patient, and that place the patient at significant risk of death, acute exacerbation/decompensation, or functional decline.
  • Patient Consent: The patient must give written or verbal consent to participate in the CCM program. They must be informed that only one practice can bill for CCM each month and that cost-sharing (a monthly copay) may apply.
  • Comprehensive Care Plan: A dedicated, electronic care plan must be established, implemented, revised, or monitored for each patient. This plan must be shared with other providers and the patient.
  • 24/7 Access to Care: The patient must have a way to reach a member of the care team 24/7 for urgent needs.
  • Continuity of Care: The practice must ensure continuity of care with a designated member of the care team.
  • Care Management & Coordination: This includes managing transitions of care, coordinating with home and community-based services, and routine communication with other healthcare professionals.
The CCM CPT Codes You Must Know

Unlike MTM, CCM codes are primarily time-based. Meticulous and contemporaneous time tracking is not just a best practice; it is a billing requirement.

CPT Code Description Minimum Time Requirement Typical Medicare Reimbursement (approx.)
99490 Non-complex CCM. At least 20 minutes of clinical staff time directed by a physician or other qualified health care professional, per calendar month. 20 minutes ~$62
99439 Each additional 20 minutes of non-complex CCM. (Add-on code to 99490). 20 minutes ~$47
99491 Complex CCM. At least 60 minutes of clinical staff time… 60 minutes ~$132
G2064/G2065 Principal Care Management (PCM). For patients with only ONE complex chronic condition. Similar time requirements to CCM. 20/30 minutes Varies
Time is the Currency of CCM: Document Everything!

Every second spent on a CCM patient counts towards the monthly total. You MUST use a software or system to track this time contemporaneously. Activities that count as “clinical staff time” include:

  • Calling the patient to check on their blood pressure readings.
  • Calling the pharmacy to resolve a prior authorization.
  • Reviewing recent lab results or specialist notes.
  • Updating the electronic care plan.
  • Communicating with the patient’s home health nurse.

A simple phone call that takes 7 minutes must be logged. A chart review that takes 12 minutes must be logged. At the end of the month, you sum up all these small increments of time. If the total is 25 minutes, you can bill CPT 99490. If it’s 39 minutes, you can still only bill 99490. If it’s 41 minutes, you can bill 99490 + 99439. This is why precise, documented time-tracking is the foundation of a compliant and profitable CCM program.

How to Build a CCM Service Line: A Step-by-Step Tutorial

Here is a practical guide for approaching a local practice and setting up a pharmacist-led CCM program.

Pharmacist’s Playbook: Launching a CCM Program
  1. Step 1: The Proposal. Identify a progressive primary care practice in your area (e.g., one that is part of an ACO or focuses on geriatric care). Schedule a meeting with the practice manager or lead physician. Your pitch should focus on the benefits to THEM.
    • The Script: “Dr. Evans, I know that managing your most complex chronic care patients takes a significant amount of time for your staff. I’m a consultant pharmacist, and I specialize in setting up and running Chronic Care Management programs. I can manage the entire workflow for you—from patient enrollment and care planning to the monthly clinical work and time-tracking—all ‘incident to’ your supervision. This will allow you to provide a higher level of care, improve your quality metrics, and generate a new, significant revenue stream for the practice with minimal work from your team. I work on a revenue-share basis, so there is no upfront cost to the practice.”
  2. Step 2: The Agreement. You will need a simple, clear contract. A common model is a revenue share. For example, you might agree to a 50/50 split of the net CCM revenue. The practice bills for the service under their NPI, and after they are paid by Medicare, they pay you your 50% share. This perfectly aligns your incentives. The contract should also clearly define your roles and responsibilities.
  3. Step 3: Patient Identification and Enrollment. Work with the practice to query their EHR for eligible patients (e.g., 2+ chronic conditions, seen in the last year). You or the practice’s staff will then call these patients to explain the program and obtain consent.
  4. Step 4: The Technology Stack. You need a HIPAA-compliant system to manage the program. Many EHRs have CCM modules, but you can also use standalone platforms. Your tech stack must do three things well:
    • Care Planning: House the electronic comprehensive care plan.
    • Time Tracking: Allow you to easily log every minute of work for each patient.
    • Communication: Provide a secure way to communicate with patients and other providers.
  5. Step 5: The Monthly Workflow. Each month, you will proactively manage your panel of enrolled patients. This involves:
    • A monthly clinical check-in call with each patient.
    • Reviewing any incoming alerts, lab results, or hospital discharge summaries.
    • Coordinating with specialists, pharmacies, and home health aides.
    • Meticulously documenting all time and activities in your software.
  6. Step 6: Reporting and Billing. At the end of each month, you will generate a report from your software. The report will show each enrolled patient and the total time spent. You will then provide this report to the practice’s biller, telling them exactly which CPT code (99490, 99491, etc.) to bill for each patient. You will also provide a performance dashboard for the practice manager, summarizing the clinical interventions and outcomes you achieved that month.

27.3.4 Expanding Your Reimbursable Services: Preventive Care and Advanced Monitoring

While MTM and CCM form the bedrock of many pharmacist-led service lines, the healthcare landscape is continually evolving, with payers like CMS recognizing the value of proactive and technology-enabled care. To build a truly forward-thinking and diversified practice, you must be fluent in the language of these emerging opportunities. Mastering Transitional Care Management (TCM), Annual Wellness Visits (AWV), and Remote Monitoring (RPM/RTM) can unlock significant new revenue streams and allow you to integrate even more deeply into the patient care team.

These services represent the next frontier of collaborative practice. They move the pharmacist’s role from a medication-centric consultant to a comprehensive care manager, actively preventing hospital readmissions, promoting wellness, and using technology to manage chronic conditions in real time. For the entrepreneurial pharmacist, these service lines are not just add-ons; they are strategic differentiators that can set your practice apart and position you as an indispensable partner to physician practices and health systems.

Deep Dive: Transitional Care Management (TCM)

The 30-day period after a patient is discharged from a hospital is one of the most vulnerable and high-risk times in their care journey. Medication discrepancies, poor communication, and lack of follow-up lead to staggering rates of readmission. TCM services are specifically designed to address this gap. These services reimburse providers for the work required to manage a patient’s transition from an inpatient setting back to their community setting. As medication experts, pharmacists are arguably the most critical players in ensuring a safe medication transition.

Like CCM, pharmacists provide TCM services “incident to” a physician or other qualified health care professional. The service requires a combination of non-face-to-face and face-to-face activities within a specific timeframe.

The TCM CPT Codes You Must Know
CPT Code Description Key Requirements & Pharmacist’s Role Typical Medicare Reimbursement (approx.)
99495 Transitional Care Management Services with the following required elements: … Medical decision making of at least moderate complexity during the service period. … Face-to-face visit, within 14 calendar days of discharge.
  • Pharmacist Role: Perform post-discharge medication reconciliation, patient/caregiver education, and coordinate with pharmacies and outpatient providers. Your detailed medication review is a key part of establishing “moderate complexity.”
  • Contact with patient/caregiver must be made within 2 business days of discharge.
  • Medication reconciliation must be completed on or before the date of the face-to-face visit.
 ~$205
99496 Transitional Care Management Services with the following required elements: … Medical decision making of at least high complexity during the service period. … Face-to-face visit, within 7 calendar days of discharge.
  • Pharmacist Role: Same as above, but for much sicker patients. Your work managing high-risk medications (e.g., anticoagulants, insulin, opioids after surgery) and resolving major discrepancies directly contributes to the “high complexity” designation.
  • The timeline is much tighter, reflecting the higher acuity of the patient.
 ~$278
Pharmacist’s Playbook: Integrating TCM into a Practice

The Pitch: “Dr. Evans, I see from your practice’s quality data that your 30-day readmission rate for CHF is a key area of focus. My TCM service can directly impact that. When one of your patients is discharged, your staff simply notifies me. I will handle the post-discharge outreach call, perform a comprehensive medication reconciliation within 48 hours, coordinate with the pharmacy, and see the patient for a dedicated medication visit alongside your provider’s follow-up. We provide a complete, billable service that improves patient safety and can significantly reduce your readmission penalties.”

The Workflow:

  1. The practice receives a discharge notification and forwards it to you.
  2. Within 2 Business Days: You call the patient to introduce yourself, confirm they have their discharge medications, and schedule the face-to-face visit.
  3. You perform a detailed medication reconciliation by comparing the hospital discharge list, the patient’s home medication list, and their pharmacy’s records. You document all discrepancies.
  4. Within 7 or 14 Days: You or the physician conducts the face-to-face visit, where your documented medication plan is reviewed and finalized.
  5. For the remainder of the 30 days, you provide ongoing management via phone as needed. At the end of the 30-day period, the practice bills the appropriate TCM code.

Deep Dive: Annual Wellness Visits (AWV)

The Medicare Annual Wellness Visit is a yearly appointment with a primary care provider to create or update a personalized prevention plan. It is a cornerstone of preventive care for seniors. While the AWV must be billed by a physician or qualified provider, pharmacists are ideally suited to perform many of its key components, especially those related to medication safety and risk assessment. By creating an efficient workflow, a pharmacist can free up significant physician time, allowing the practice to see more patients while ensuring the AWV is comprehensive and high-quality.

The AWV CPT Codes You Must Know
CPT Code Description Key Components & Pharmacist’s Role Typical Medicare Reimbursement (approx.)
G0438 Annual wellness visit; includes a personalized prevention plan of service (PPPS), initial visit.
  • Pharmacist Role: You can conduct the Health Risk Assessment (HRA), review the patient’s medical and family history, and perform a thorough medication reconciliation to identify high-risk drugs. You gather all the data so the physician can focus on the final review and care planning.
 ~$173
G0439 Annual wellness visit, includes a personalized prevention plan of service (PPPS), subsequent visit.
  • Pharmacist Role: Same as the initial visit, but focused on updating the information from the previous year. You can review medication changes, assess adherence, and identify any new risk factors.
 ~$118

Deep Dive: Remote Patient & Therapeutic Monitoring (RPM & RTM)

This is one of the most rapidly expanding areas of healthcare reimbursement and a massive opportunity for tech-savvy pharmacists. RPM and RTM involve using digital devices to monitor and manage patient health data outside of the clinical setting. RPM typically covers physiologic data (blood pressure, glucose, weight), while the newer RTM codes cover non-physiologic data, including medication adherence and response.

These services allow you to proactively manage chronic diseases like hypertension, heart failure, and diabetes, intervening before a patient’s condition deteriorates. As with CCM, these services are provided “incident to” a physician, making them a perfect service line for a consultant pharmacist.

The RPM/RTM CPT Codes You Must Know
CPT Code Description Key Requirements & Pharmacist’s Role Typical Medicare Reimbursement (approx.)
Remote Patient Monitoring (RPM) – Physiologic Data
99453 Remote monitoring of physiologic parameter(s) (e.g., weight, blood pressure, pulse oximetry, respiratory flow rate), initial; set-up and patient education on use of equipment. One-time bill per patient. Pharmacist can perform the device setup and patient training. ~$19
99454 …device(s) supply with daily recording(s) or programmed alert(s) transmission, each 30 days. Billed monthly for the cost of the device. Requires at least 16 days of data transmission in a 30-day period. ~$49
99457 Remote physiologic monitoring treatment management services, first 20 minutes of clinical staff/physician/other qualified health care professional time in a calendar month. The core management code. Pharmacist reviews readings, interacts with the patient, and makes adjustments to the care plan. ~$50
Remote Therapeutic Monitoring (RTM) – Non-Physiologic Data (e.g., Adherence)
98975 Remote therapeutic monitoring (e.g., respiratory system status, musculoskeletal system status, therapy adherence, therapy response); initial set-up and patient education on use of equipment. Similar to 99453 but for RTM devices (e.g., smart pill bottles, digital inhalers). ~$19
98977 …device(s) supply with scheduled (e.g., daily) recording(s) and/or programmed alert(s) transmission to monitor medication adherence, each 30 days. Monthly device code for RTM. ~$56
98980 Remote therapeutic monitoring treatment management services, physician/other qualified health care professional time in a calendar month requiring at least one interactive communication with the patient/caregiver during the calendar month; first 20 minutes. The core RTM management code. Crucially, it requires at least one “interactive communication” (a phone or video call) each month. ~$50
98981 …each additional 20 minutes. Add-on code for RTM management time. ~$41

27.3.5 Building the Hybrid Practice: A Financial Case Study

Let’s revisit our entrepreneurial pharmacist, Dr. Evelyn Reed. She has successfully launched her cash-pay geriatric consulting service, “Clarity GPC.” Now, in Year 2, she decides to diversify by partnering with a local primary care practice to provide CCM and TCM services.

The Partnership Agreement: Dr. Reed and the practice agree to a 60/40 revenue split in her favor (she keeps 60% of the net revenue generated) as she is providing all the labor and the technology platform for the service.

The Service Expansion Goal:

  • CCM: Build a panel of 100 CCM patients over the course of the year. Assume an average of 25 minutes of work per patient per month, allowing the practice to bill CPT 99490 for each patient.
  • TCM: Manage 5 TCM patients per month, assuming 3 are moderate complexity (99495) and 2 are high complexity (99496).
Financial Impact Analysis: Adding Reimbursable Services
Service Line Calculations Total Monthly Gross Revenue (for the Practice) Dr. Reed’s Monthly Net Revenue (60% Share)
Chronic Care Management (CCM) 100 patients x $62/patient (CPT 99490) $6,200 $3,720
Transitional Care Management (TCM) (3 patients x $205) + (2 patients x $278) $1,171 $703
Total New Reimbursable Revenue $7,371 $4,423

By adding these two reimbursable service lines, Dr. Reed has created an additional $4,423 per month, or over $53,000 per year, in highly predictable, recurring revenue. This new revenue stream is completely independent of her cash-pay clients. It makes her practice far more resilient, enhances her cash flow, and solidifies her relationship with a key referral partner. This is the power of the hybrid model.

27.3.6 Conclusion: From Service Provider to Strategic Partner

Building service lines around MTM, CCM, and other reimbursable codes is a strategic evolution for your practice. It marks the transition from being a solo practitioner seeking individual clients to becoming an integrated partner in the healthcare system. This approach requires a new skill set—mastery of CPT codes, meticulous time-tracking, and the ability to articulate a value proposition to other providers. Yet, the rewards are immense.

By creating a hybrid practice that blends the freedom of cash-based services with the stability of reimbursed services, you build a business that is financially stronger, clinically more impactful, and professionally more integrated. You are no longer just a consultant; you are a vital component of the value-based care ecosystem, demonstrating your worth not only through the outcomes you achieve for patients, but in the language of the system itself.