Mark Steward, PH.D.
Mark Steward, PH.D. is an Adult Development & Aging Psychologist in Newton Centre, MA, registered under NPI 1821152828. This provider registers 7 separate taxonomy codes, which usually means they practise across more than one recognised specialty. NPPES records them as a sole proprietor, meaning the practice is not incorporated as a separate legal entity.
Getting there
The practice address on file is 53 LANGLEY RD SUITE 340D, Newton Centre, MA 02459. We have not yet mapped what surrounds this office — parking, transit, and nearby pharmacies are added as our data collection reaches each location.
Credentials and Medicare
| Licence | State | Specialty |
|---|---|---|
| 4784 | MA | Adult Development & Aging Psychologist primary |
| 4784 | MA | Clinical Psychologist |
| 4784 | MA | Clinical Child & Adolescent Psychologist |
| 4784 | MA | Psychologist |
| 4784 | MA | Family Psychologist |
| 4784 | MA | Group Psychotherapy Psychologist |
| 4784 | MA | School Psychologist |
This provider holds licence 4784 issued in MA. A licence number in NPPES reflects what was filed at registration — it does not confirm the licence is still active today.
This NPI does not appear in the PECOS Medicare enrolment file. Providers who do not bill Medicare — or who bill only through a group's enrolment — will not appear here. It is not a sign of any problem with the registration.
What Adult Development & Aging covers
A psychologist who specializes in geropsychology, which applies the knowledge and methods of psychology to understanding and helping older persons and their families to maintain well-being, overcome problems and achieve maximum potential during later life. Professional geropsychology appreciates the wide diversity among older adults, the complex ethical issues that can arise in geriatric practice and the importance of interdisciplinary models of care. NUCC Health Care Provider Taxonomy, code 103TA0700X
All registered taxonomy codes
This provider registers 7 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 103TA0700X | Adult Development & Aging Psychologist Adult Development & Aging | 4784 | MA | primary |
| 103TC0700X | Clinical Psychologist Clinical | 4784 | MA | |
| 103TC2200X | Clinical Child & Adolescent Psychologist Clinical Child & Adolescent | 4784 | MA | |
| 103T00000X | Psychologist | 4784 | MA | |
| 103TF0000X | Family Psychologist Family | 4784 | MA | |
| 103TP2701X | Group Psychotherapy Psychologist Group Psychotherapy | 4784 | MA | |
| 103TS0200X | School Psychologist School | 4784 | MA |
The taxonomy records how the provider classifies their own practice. It does not confirm which conditions they currently treat, whether they are accepting new patients, or which insurance they take — call the office for that.
Full NPPES record
An NPI-1 identifies a single person. It stays with the clinician for life, even if they move practice or change state, which is why the address on file can lag behind where they actually work today.
| NPI | 1821152828 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Dec 21, 2006 |
| Last updated | Sep 11, 2025 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | PH.D. |
| Practice address |
53 LANGLEY RD SUITE 340D Newton Centre, MA 02459 (617) 484-7604 |
| Mailing address |
17 EDGEMOOR RD Belmont, MA 02478 |
| Other identifiers |
W04555
· BLUE CROSS BLUE SHIELD (MA) |
Number check
How the check works, step by step
Every NPI carries a Luhn check digit — the same scheme used on credit cards. CMS prefixes the number with 80840 before computing it, which marks it as a US health identifier.
| Digit | 8 | 0 | 8 | 4 | 0 | 1 | 8 | 2 | 1 | 1 | 5 | 2 | 8 | 2 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 8 | 4 | 1 | 2 | 5 | 4 | 8 | 4 |
Sum = 62 · next multiple of 10 = 70 · check digit = 8 · actual last digit = 8
A valid check digit only means the number is well-formed. It does not mean the provider is licensed, active, or in good standing — those are separate questions answered by the sections above.